We had two Montanas, second one was flawless (2007), first one not so good (2003). However, it sounds like you are still way back in the floorplan stage, so I wouldn't stay with any specific brand. Pick a few floor plans you like and sit in them a while to get the feel, it will come to you, but not before several exhausting days where you just want to give up.
Brandwise - with a few exceptions, they are all pretty much the same - almost homogenized with the same frame, suspension, etc, especially within a specific price range.
Truckwise - you're a ways away from determining that. Take the factory pin weight and ad 1,500 lbs if you like to haul water, add yourself, hitch, and any gear in the truck, and find a truck that will handle that payload.