I’ve owned a 24-Ft Class C, and rented 27- and 30-Ft Class Cs for 2- and 3-week trips with other family members. For me, there is no doubt that a 24-footer is more maneuverable and easier to park than a 30 footer. With my shorter Class C I didn’t think much about entering any gas station or grocery store parking lot without much planning, feeling confident I could always get out somehow. When driving a 30-footer I always plan ahead.
Driving has also been a little more demanding for the larger Class Cs. While all were on same Ford E-Series chassis, cross winds and semi trucks affected the longer Cs more than my shorter 24-footer. Having said that, my wife has driven them all without issue. In fact, the only issue we’ve had is that she drives too fast for my taste. I don’t think she takes into account what could happen in case of a blowout in the middle of a curve, etc. A motorhome isn’t a sports car or minivan, and that should be respected.
As to size, some people live well in 400 square foot apartments, and others have 5,000 square foot houses. I don’t think you can go by what others think is best size, which is why I often recommend renting first. It’s expensive but can save more in long run.
We now travel in a van-size camper most of the time, and occassionally rent only when we need more space; which we haven’t done in a few years because the van is good enough for the two of us, particularly since our dog passed. And as tourers, we don’t mind spending the cost to stay in hotels or National Park Lodges once in a while if feeling cramped.
For the two of us, I’m hoping to keep it at 24-Ft or shorter as long as floorplan and storage is well thought out.