Grangrey4,
We are a great test case for you....
We have a 23' Class A that has not been made for 40+ years, so that is not an real part of the issue.
But what matters here is that we frequently take grands (any of 6) with us on specific excursions.
For a one day trek to something nearby, we might take the three older boys, (the elder GD has not expressed any interest yet) and that is no issue.
For an overnight, we have never tried more than two of the boys at a time and even then, before departure I lay down the law that if there are any problems, we turn around. (There was the start of one just once, and when I asked if we were going to turn around, that ended it.)
I will not say that is not a little tight some times, but with effective cooperation, it can work.
As said, borrow or rent what ever you can to try out. One weekend will in anything will form a lot of opinions.
Matt