Our floor plan probably wouldn't suit you as we have the crow's nest for the main bed and the fold-out couch which will fit two adults and the dinette/bed suitable for two children.
IMHO, we observe that with the main bed in the rear, then the storage door opens under the bed from outside. We like our floor pland because both sides have large windows and the other floor plans have a tiny kitchen window on the right, which belies the model name VIEW.
We bought used and its our first RV. The 6 cylinder 3 liter turbo diesel has been really good with decent power and MPG.
Itasca and Navion are Winnebago names and are almost exactly the same thing.
Newer versions than ours have bigger towing capacity but we are fine with what we have.
Don't forget that the M-B specs on all the fluids, etc are important from a warrantee perspective.
M-B Spec listAnytime you have children you will have problems here just as much as anywhere else. In particular we have faucets left on by the grandkids because we turn the water pump off, then when we turn it on we get minor flooding.