Make sure you get the weight of the travel trailer...a lot of the older styles were fairly heavy since they were built with heavier materials. Also make sure you run sway control!!!!
I have towed all sorts of things with my 2001 sport trac (w/v6), however I live in flat Florida so I don't have the problems with up and down hills except bridges and even those are pretty mild grades... I would not be able to comment of if it would be able or safe to tow over the recommended limit in a more mountainous terrain.
The most I have ever done was about 7600 or so with this boat from ft pierce to the FL keys
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If you are going to push the limit though you NEED a better transmission cooler like a b&m with fan and something like a scan gauge to watch the Trans temp. Also you need to remember to drive very carefully because it is a case of small truck vs. large load.
**Also proper trailer loading is the most important thing of all.