I recently talked with Tundra specialist at a recent Bass Master event and he stated it is strongly not recommended, due to the short bed. But if it has it in it, I would contact the previous owner and ask them to see what they were pulling>
A close comparison, my dad had a Chevy with a super short box like the crew max, he was able to pull his 5th wheel camper with the truck, although he did over jackknife once while backing up into a single wide drive way off an narrow road, no major damage really helps if you have a spotter. I say all the power to ya!!!! Good Luck!!