Just some info. to help answer your questions. We have a 27 foot Class C that has crossed the country a couple of times. We drove through, had dinner in towns like Ft. Collins, Estes Park, Jackson, Cody, and others, and never felt the need to have a toad. We even parked at the Santa Monica pier parking area without difficulty. So, relatively easy to drive and park for a big vehicle. Others like having a toad, but that's a personal choice.
Many owners of the brand we own boondock and even fulltime in their 27, including forest service roads. But, as noted by other posters, its the OCCC that's important. So, I think a family of three will find a 24-27 footer adequate for most of your needs.
Lastly, when our children were little, we put their car seats on the dinette bench seat and held them in place with the RV seat belts. In that RV, the dinette was immediately behind the front passenger seat.
Hope this helps.