Will a FW back into the same spot as a similar sized BP?

I have never seen a 5er have problems getting into any campsite, but I've seen lots of TT's struggle. I think the 5er will be much easier for you than the TT. When you first get the 5er, take it to a parking lot and practice a few times backing and turning before you get home. It will pay off big when you finally do get home.