I think some of the posters here must have assumed you meant to tow a full size travel trailer. The height on a full size trailer causes both wind drag from the frontage, and also the sway (push) from big rigs blowing by (not to mention the fact that even a V8 Explorer can only tow about 7,000 lbs tops).
We have been using our V6 Mountaineer to tow our pop-up (Fleetwood Bayside), and it has worked out just fine. I bought it with the tow package (including the towing axle ratio). With a level hitch and a sway bar, we cruise along at 65 -70 mph with no problems. On steep inclines, you definitely feel the trailer behind you though.
I hope to move up to a Suburban soon. We have 3 kids and the third row seat Mountaineer is great for fitting them in, but leaves very little space for cargo. The alternative is to squeeze the 3 kids in the second row, which is no fun for long distances.
So, you might want to think about a pop-up as a way to get started with your current vehicle.