Beyond and LHTH are not hard to do at the same time - in fact, we enjoyed it very much!

LHTH takes around 20-30 minutes a day, so no worries there. For Beyond, here are the suggested time allotments for each box...
Reading About History Box: 10 min.
Poetry and Rhymes: 5-10 min.
Bible Study and Music: 10 min.
Rotating Bottom Left Box (Artistic Expression, History Activity/Timeline, Geography, Science twice weekly): 15-20 min.
Language Arts Box: 15 min. (spelling/grammar)
Reading: 15 min. if doing the Emerging Readers and 20-25 min. if doing DITHR 2/3
Math: 15-20 min.
Storytime: 15-20 min.
Beyond has a great ebb and flow of sit down type things and get up and move type things. If you could read the Reading about History book and Bible study (sit down things) while the little ones are eating their snack and drinking their juice, then you could have the little ones all march around to the Music with the older ones a few times. After that, everyone can enjoy the poetry, and it is short. You can then have a play dough time for the littles (or something hands-on at the table), while you do the hands-on rotating box with the olders. Wah-la! You then have the left side of the plans of Beyond done already!

For the right side, if you could have the littles watch an educational video (i.e. Barney), during that time you could do the Math Lesson and Storytime with your olders. Then, each of your olders could take a turn playing with the youngers, while you individually did their LA box and Reading lessons. I'm just throwing out some ideas, but you can see how you can manage several ages well this way, and enjoy your days together!

HTH!
In Christ,
Julie