It's really just pick a floorplan that you like and make sure it has had no leaks and all the appliances work, there isn't a heck of a lot of difference in brands, the appliances are all the same too. You're looking for used so you won't have all that big a choice.
 The newer you go the better the chance the manufacturer has worked out the kinks as far as leaky seals around the bunk doors. If it were me I'd stick with one of the bigger brands like Jayco or the Forest River Roo's. Starcraft (owned by Jayco) has gone through some convolutions since 08 due to the economy so might be best avoided as things changed a lot year to year.
 There are relatively few manufacturers, each making a number of lines. For the most part the lines vary a little in quality going from their most expensive to the least. Go to the Forest River web site and look at all the different Lite Travel Trailers and you'll see what I mean, at least 3 of those have HTT's in the line up.
 Again, differences are small and you won't have that much to pick from. So find one with a plan you like for a decent price and go over it as well as you can.