Not too many good 4 season trailers out there but the new units from outdoors rv from nash are impressive...
They are in the links I posted..
You did state 4 season, and I probably would have nothing lower living in CND...
Having all the kids you have doing a large style bunkhouse with full beds gives kids lots of room.. as I linked
Less chance to fall out of the bunk because of walls on both sides. The other style bunk house units tell a 4 year old not to roll over in thier sleep...
Let the young ones sleep together..
When kids get bigger put one on sofa couch and one on dinette..
Also has the outside bath door you atated it should have..
Dont know how much better you can do then that unit .