Well...here is my advice and thoughts...
When you say "behind"---do you mean as in important skills, like math and grammar/spelling/reading? Or do you mean just the guide as a whole, and you need to get them caught up to whatever lesson they should be on if they had continued with HOD? That's what I think you really have to sit down and look at and come to terms with...
From what I can see from your signature, you have your hands very full! This is only my opinion, but here's what I would do to make each day livable, doable, and peaceful.
1) Contact Carrie for some ideas or her opinion of how you can set up Bigger Hearts for independent work for your 9 y/o---assuming that she's able to do some of it independently---maybe you could set up a small index card box with a card for each subject, then let her pull a card for whichever subject she can do independently, and check it off as it is done. Carrie can tell you, and you probably know best which things your 9 y/o can try to manage independently, then do readings from texts while the others are coloring/napping/writing/etc... That should get you back on track with the guide, and give you a feeling of forward progress---and free you up a bit for the other children's needs.
2) Is either your 5 y/o or 7 y/o a reader yet? For either or both, get them going with the Emerging Reader list (is that in LHFHG?) daily or work each day with emphasis on reading skills. To me, working on reading/phonics skills is essential---everything else is gravy at that age.
3) For the 5 and 7 y/o --if you can't get to the Singapore lesson, or they can't do it independently, let them play and work with manipulatives every day. Try to get to the math lesson a couple or three times per week, but keep them playing/working with the manipulatives. This will help to keep those wheels turning in their minds for how math "works". Maybe your dh could do the math lesson with them in the evening, and you could just save it for then (don't know if that's an option, but just suggesting it...) Read the history or Bible lesson to these two children while the 9 y/o is doing some of her independent work, then switch up and work with the older child.
4) For the 3 y/o---how about a plastic washtub of playthings to interest him? I've read about those preschool activity bags, but don't know if you have the time or energy to get something like that together. I wouldn't stress over getting lessons done at the age of 3. You've got plenty of time for that later. Let this child listen in on the LHFHG Bible/history lessons, maybe try to do the letter/alphabet focus of the week from LHTH, or play with foam letters or a cookie sheet and letter magnets, or color/draw with the others while they're doing their written work.
5) You have several children to take care of, and to me, you need to simplify, simplify, simplify... I know that I could not do three programs with a small baby to care for. Take it slowly, try to get some advice from Carrie for making parts of BHFHG independent work, and focus on the 3 R's for all school-age children. I really believe if you can come to terms with being a bit "behind" in the manual, there will soon start a natural flow to your day, and you can see progress. Try to decide what you can keep, and what you can let go for the time being until things settle down. Let the 3 school-aged children all work on handwriting together (at their own level). Let the 9 y/o read some of the Thornton Burgess stories to the youngers if possible--this will hone those reading skills, and all get two things done at once!
6) Schedule in some time during your day for "Mommy time". Let the kids work quietly on handwriting, practicing math facts, or just reading/looking at picture books by themselves. You've got to take care of yourself in order to care for everyone else! Have some warm apple cider or a hot cup of tea, and take at least 30 mins. or so for yourself---then gather up the troops and let everyone help with folding laundry, washing dishes, setting the table--those kinds of things. Something I learned from reading of Montessori is the learning of basic home skills at the early age. I think it's great, and you definitely can use the help!
7) Hang in there...Carrie has written these guides to make it
easier for you. Take what works for now and use what you can. I think you'll be surprised how much better things will go if you place a priority on certain things from the lessons, and let a few things go. You can always take Saturday afternoons (when it's raining or too cold) to catch up on the science or geography lesson for the week.
Hope some of this helps. Sorry it's so long-winded, but I'm not too good at being succinct with my explanations!
