The pin weight on a 10k GVWR fifth wheel will be 2000 lbs loaded (based on 20% factor). One you add 300 lbs of passengers, 150lb hitch, 100 lbs fire wood, 100 lbs tools, and 50lb Fido to the truck; your truck is loaded with 2,700 lbs of weight. I don't know of a half ton truck that has that kind of payload rating. Most are around 1500, some as high as 2,000 (max tow package, etc).
Personally, I would not tow any rv with a GVWR of over 7500 with a half ton. I also believe that the term "half ton towable" is a marketing term used much to loosely to broaden the marketing of heavier rvs to the huge market of half ton truck owners.
I believe rv'ing should be a fun, safe, relaxed and worry free experience. Nothing is worse than rolling down the interstate with an rv behind an underrated truck. I have been there and done that.