I'll go ahead and be that guy...
If it would be an option, you might want to consider looking into a tow vehicle that would be better suited for towing. Reason being, you are probably not going to like towing a loaded 4000lbs + trailer with your 4-Runner at altitude since that naturally aspirated engine is down on power out here in the Rockies. If you could consider moving up to a 1/2-ton and maybe one with forced induction (turbo), it will open up A LOT more options for you regarding selection of travel trailers. You won't be able to tow everything out there but you'll get a ton (pun) more options in trailers and be able to load it better with more creature comforts.
If that option sounds reasonable to you, go and look into trailers first to see what suits you. Floor plans are generally the biggest factor for many. Find something, and then match a tow vehicle to that trailer. Will help avoid a lot of headaches going this route.
Good luck with your search!
