Sorry to be the bearer of bad news but no. Even though the 210 lists a weight of about 3300 lbs once you take into account all of the add ons like battery, propane, awning, and gear you almost certainly be over 5000 lbs Then you also have to take into account the weight of passengers, the WD hitch & gear in the truck itself which combined will likely put you several hundred pounds over the 5000 limit. That's without even getting into things like tongue weight.
Here's a thread that discusses a similar towing setup:
http://www.funfinderclub.com/phpBB2/viewtopic.php?t=720
and one that with a different setup by a good description of how to determine safe towing capacities.
http://www.funfinderclub.com/phpBB2/viewtopic.php?t=702
I'm sure if you search you'll find more.
Not trying to discourage a potential new FF owner, we love our 210 WBS, but I just don't think towing one with Xterra is a safe way to go.
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