Two actual possibilities:
1. It sounds like you will be down there friday night, saturday, Sunday and Monday. That is a long time to be with friends with the kids. People need their own space after a couple of days. It is more likely that you will all get on each other's nerves after spending that much time together. You will probably have a better over trip is you spend at most 3 days not 4. Not sure how old your kids are but mine are small and nights in a new place don't translate to good sleep so we try to minimize the overnights by leaving early in the morning.
2. The other thing to consider is how tired you get at night driving. Capitol reef is 4 or 5 hrs so with no stops you will be getting there at 10 pm. Do you start getting tired while driving so late? If so then you have a safety problem on your hands.

Good luck.