It's an interesting problem. You want a light duty truck and a heavy duty trailer.
First, the truck. Yes, there are 1/2 ton trucks that can pull the trailer you want, but you are also putting in four adults and all the gear with them too. So that really cuts you back. You will need the heaviest duty truck you can find.
Now you want to tow a four season trailer. Again, there are some made, but to go to a true four season trailer, well that makes trailers heavy. To sleep four adults in three beds usually means one on the dinette, the other on the pull out couch. That usually means a slide.
These are some of the nicest trailers out there if you can find one. Check them out here.
Triple E Topaz. They stopped making them in 2009, I have a 2009 Fifth Wheel. Beautiful rigs.
I would still like a 3/4 ton in front of most of them. Crew cab, long box.