Hi,
Do you have any more information for us to go with?
Do you know the trailer GVWR, pin weight (normally empty)? Location of the fresh water tank helps as well.
If you could find a used Glendale RV toyhauler, it has a much lower pin weight, and both fresh water tanks are located between the axles, so they do not add to much pin weight.
Your motorcycles will take away pin weight because it is behind the rear axles of the trailer, a good thing in your case. If you need a larger garage, then buy what you will be happy with, not someone else's 'opps I need something larger now so I need to trade up again'.
Check out this website.
RvSearch.com You can find many toyhaulers, even some diesel class C with the GMC chassis and a 19,500 GVWR. Just click on "Toyhauler" and enter your zip code and within 500 miles, you should get a good list to pick from. Do not pick a manufacture or type (class C or trailer).
Any travel trailer type will have a much lower hitch weight, but have all the drawbacks of a travel trailer in strong winds. I agree that a fifth wheel will tow much better, but the Hensley hitch, or it's upgraded version will work well with a travel trailer.
Fred.