First I'd get yourself down to an RV showroom & get a feel for the sizes & layouts. When i was looking I thought i knew just what kind of floor plan i wanted.
Bed in the back with the doors wide open gazing over a lovely sunset ect.
In reality when i went to see the van that i wanted it felt incredibly dark & claustrophobic, & i'm small!
I still have a vision of my perfect rv & will get there eventually, but in the mean time i'm really happy with my twin bed, bathroom in the back. It feels much more open & spacious. Even though it's exactly the same size. And the price was right.
For months i skipped over any ad where the rv didn't have the bed in the back.
Who knows how many deals i missed!
There're going to be a compromises with whichever one you choose, unless you've unlimited funds & build it yourself.