It's not a matter of "puttering along at 60". Most of us here only tow at 60-65 for safety and limitations of ST tires. All I'm suggesting is that you are more than likely going to find that this is not at all a good combination and you'll hate the towing experience. I'd really hate to see you go into this and find out after a few trips towing you're looking at trucks anyway. The vast majority of people in your situation do exactly that.
Regarding the trailer, no matter what used trailer you look at you need to look for evidence of water damage. Get on the roof and look for dried and cracked seals. In fact look at everything for this. Hybrids are only prone to leaks in the bunks because people fail to take care of them. We're on our second one and have never had a leak that was not due to a dried out seal on the roof. We had our first hybrid for 10 years. Open all the beds and look at the seals around the bunk wall. Are they dry or soft and pliable? Look for evidence of water anywhere. Have the owner or dealer demonstrate that all the appliances work, heat, ac, etc.
