Should I be worried about an RV that is too long?

Just don't be supprised when you knock the lower rear corner off manuvering around a fuel stop or campground or the top front corner when you forget about the low overhang. It is likely to happen and can be expensive.

IMHO the bigger the rig, the bigger the stress and headaches. By all means, get what will make you happy but you can get too big to have fun.