If are towing a popup, a vehicle with a towing capacity of at least 3500 lbs would be your best bet. Most (but not all) towing capacities are rated with one 150lb passenger. Every pound added after that is subtracted from the tow rating. Additionally, even if your popup weighs as little as 1000-1500lbs, by the time you have your gear packed you'll be substantially higher than the empty weight.
I'm biased, because I own one, and have towed with it extensively, but would recommend a 2004 Pilot. Should be within your price range. Other options would be Highlander, Outlander V6 as mentioned, Pathfinder, etc.
Edit- just noticed your criteria of 5 years old max. Pilot and Highlander may be out. Additionally, most minivans are rated to 3500lbs with the tow package, so thats another option.