With your Silverado, are you maxed at about 8000 - 10000 towing capacity? Our '03 F150 5.4 is rated for 8000#. If so, you should be looking in the 6000 - 7500# range loaded and ready to roll.
Dick always suggests Trailmanor, although they rarely come close to what the OP is looking for, but couldn't hurt to look. Be advised they are not inexpensive and some consider a PITA to keep in good order with the raise/lower requirements
Agree that the screenroom could certainly gain you some living area as long as you don't have inclement weather....that's when the awning needs to go in ASAP.
Any chance the second bedroom is going to be used by teens or close?? Often, they're just happy as a clam to have their very own tent set up on the same site. Or...any chance you could look further into a toy hauler and mod that into a bedroom? What are the toys? It's not often that someone doesn't come up with some specific makes and models to take a close look at, but you may have pushed our limits. Good luck.
