Online resource, can search by length, once finding a FLOORPLANS you would like, then visit MFG sites to get approximate weight ranges.
RVTraderVisit local dealers, to see, go in, learn about units, experience "Quality" of units. Visit RV shows if possible.
Search Tow Limits here, although truck rated 7,000 lbs, depending on how much you plan on towing, 6,000 & up trailers probaly out of "safe"/'Comfortable range for the truck. (gets debated all the time here).
Newer trailer builds of 27-30 ft trailers, if a "Lite" or "Ultra Lite" version, very well will be in 4,500-5,500 weight range.
Good Luck and enjoy the adventure.
Markiemark:C
Btw: Myself and my Wife, travel with a Dutchmen Kodiak 200QB (24ft TT). Have been super pleased with: Weight 4,000 lbs, before we added all our stuff for traveling/camping, probaly added 1,000 lbs of stuff, travels great with my Tundra (would not want too much more wieght), Open floorplan (no crazy walls blocking in), hard-walled shower, lots of cabinets for storage as traveling, no-slides (no added issues or maintenance), can get in & out of most to all places/sites/gas stations, etc. Downside: cramped if visitors inside with you.