As already mentioned, we wanted a bed you could exit without crawling over your spouse, ours is in the front. We wanted a big bath with linen closet so it takes up the entire back.
Our view is to the sides. In a campground it does not make much difference.
I will say many of the TT I have seen have the water tank over the axles regardless of the interior lay out.
I have a 25 ft. TT with a 42 gallon Fresh tank located over the axels and have never notices any handling difference tanks full or empty.
The Black and Grey tanks are located in the rear. We usually dumped before we leave camp unless it was a short stay. Therefore, so we rarely have more than more than 1/3 full in them.
Take your best guess at the TT you think you want, then rent a similar unit for a week or two. It is expensive but you learn a lot before you spend the big bucks.