Showerofblessings,
Welcome to the HOD Board. We're glad to have you here!
As the ladies are helping you talk through possible ideas, I wanted to pop-in and share a few things that will make your year go much better. First of all, let me begin by having you read a post I shared a little while ago about my own journey with Ambleside Online with my oldest son. The reason I share this is because it will help you better understand the suggestions I am going to make after you get done reading the post. Simply scroll down at the following link to read my post:
viewtopic.php?f=6&t=15380
Now that I've spent some time qualifying my next comments, I am going to suggest that you not spend time matching Ambleside Online's books to add in as Storytime books. The reason for this suggestion is that the story time books in our guides were chosen specifically for the age and listening level of the HOD guide and chosen to add a needed element to the history study done at that time in the guide. Often the Storytime books are scheduled to add another point of view or differing perspective to a lesson. Or, they may be scheduled to bring to life a little known aspect of the time period that is needed to better understand it. Or, they may be chosen to bring forth a spiritual awareness of the time period and to bring the listener closer to the Lord, sharing ways of dealing with trials and tribulations in a God-honoring way.

By substituting other titles in their place, you'll miss important connections that will bring your study of history to life!
One question to weigh before substituting is whether the book list from Ambleside Online is so exceptional that it needs to be substituted in place of books that were specifically chosen to fulfill a special purpose for each part of the HOD curriculum. While I do feel that some of the AO books were very good (and we do use those books along the way within our curriculum), I was less sure of the stellar qualities of some of the other books we read through AO. Keep in mind that only some of the books on the AO list were actually ones selected by Charlotte Mason. Additionally, it's good to note that Charlotte Mason did not have access to the wealth of reading material that we have available today. I do know from what I've read that Charlotte Mason spent extensive time choosing books each year for her students to read. That was where her focus always was, which means I think she might be surprised to discover that we aren't using some of the newer wonderful book selections and instead are simply continuing to pick off of her older book lists! What we schedule within HOD is a mix of the old and the new. We spend much time on the book selection process, sifting and sorting to find the very best mix. The emphasis is always on the books. If you try what we have scheduled I think you will be pleasantly surprised.
Secondly, through my years with AO, I found that the book selections were consistently very difficult requiring much time to process. While that was fine when doing only a few books each year as AO had scheduled, by the time we add in the volume and richness of the HOD program; to add an AO book on top of it would be expecting way too much. To do that would be replacing a book that was meant to function in one way with a book that was meant to function a different way in a different curriculum. You will discover as you do HOD (and probably did discover as you did AO) that both of our guides are so much more than just a book list. They are a philosophy or a way of learning. While within AO, each book has a specific place and a specific purpose, the same is true within HOD. This means that the less substituting you do, the more the program will function the way it was designed. This makes for less stress and more enjoyment all the way around.
While you could use some of the free reads from AO with DITHR, I wouldn't be very quick to plug too many of those titles into DITHR either. The books on the free reading list for AO are very advanced and often are scheduled way too young, in my opinion. Yes, the child may be able to read a book like that at the age suggested, but how much richer would his/her experience be with the book if he waited until he was a bit older? Also, keep in mind that with DITHR we are having the child really think critically about the story and draw out connections and themes. This is not easy to do and if on top of that a really difficult book is added to read at the same time, the lessons will become too hard too fast. When using DITHR at first, it is better to err on the side of the book being too easy, rather than too hard, simply because of the extra mental work required to complete the DITHR exercises!
Some of the AO books are wonderful, and as such we have included them within our DITHR packs already. But others on the AO list have issues, which we discovered as my older son was reading them. I found that simply being on the AO list did not guarantee that a book was great or that it could be handed to my child without needing pre-reading! While you may potentially have some issues with our books as well, we make every effort within our guides to warn you of those upcoming issues, leaving you with less pre-reading to do. I think you will also find that the balance of books within our DITHR packs help your year with DITHR flow better, as the books are chosen to create an ebb and flow as to difficulty, length, and content throughout the year.
So, I would encourage you that if you have decided to do HOD, to do HOD. Try your best to stick with the suggestions and the scheduling we make. Make good use of your AO books for free-reading or family read aloud time, but don't spend tons of time trying to plug them into an HOD guide.
As far as teaching the guide goes, I would highly recommend sticking with the plans as close to the way they are written as possible. Routinely shifting boxes to other days or making a schedule that takes the plans apart will quickly result in losing both the flow and the ease of use of the guide. When we talk to families who have left HOD and then returned, they always share that they did too much substituting and too much moving of boxes and randomly moving through the guide. This seems to be a pitfall for those who aren't successful with HOD. When families return, they often share with us their goal to stick much closer to the plans. So, I suggest trying hard to complete a day of plans within a day. If you do have to slow down, split one day of plans over two days as needed. I've had to do this for seasons myself! But try not to move boxes from various parts of the plans to an extra day at the end. Each day is specifically written to make connections among the boxes of plans on that day. Moving boxes means the connections fall apart and the plans begin to feel random and fall apart too.
You can do 3 guides, as we have done 4 at our house for years. But, I have to honestly say I couldn't have done 4 guides if I had done many of the things being pondered in this thread. This is because adding and substituting resources takes time to plan, which often results in precious teaching time lost. It also means that no one can just open their guide and go for the day (including you). Moving boxes to different days takes time to plan and manage, and again now no one can just open their guide and know what to do today. It also makes the program feel random as the connections are lost. Adding a time intensive math program for multiple students will really add time to your day. With this in mind, I would look carefully to see if
any of your kiddos could benefit from Singapore math. It is easier to start a child in Singapore math when they are younger. Perhaps, you could do Singapore with your younger kiddos and just do Saxon with your older child or children. These are all things to consider, to keep your day manageable and your teaching time in line.
Of course, you may feel differently and as the teacher you will need to make your own decisions. We do have many families who are successful with HOD who use a different math program or a different grammar program. We do have families select their own books for DITHR and thrive with the program. You'll just need to bear in mind how much time each of these changes are adding to your day or whether the substitutions are making your day go very long. I pray these thoughts will be of use to you as you ponder what is best for your family. I've learned the things I am sharing with you the hard way, in the trenches from years in the classroom and years schooling my own kiddos with HOD. I just want you to have every opportunity to enjoy HOD with your kiddos and not get overwhelmed.
Blessings,
Carrie