You don't say if it is used or new. If used, I recommend something new enough to get a 6+ speed transmission. If given a choice between say a 2007 Tahoe with 3.73 or 2009 with 3.42, get the 2009 as it comes with a 6-spd and far better overall gearing than the axle ratio implies.
I would not consider anything with a naturally aspirated V6. Even a 2014+ V6 with over 300hp makes a lot less torque that V8's of even 10 years ago, under 3000rpm where most people prefer to drive. As you know from Class C ownership, RVs are not aerodynamic. It takes a lot of power to push/pull anything high walled through the air at 65mph.
Payload can be a problem for many vehicles which needs to support whomever is in your vehicle, cargo in the tow vehicle, and trailer TW. Tongue weight of 700-900 pounds is possible for that trailer.
If you are looking at new 2015s, I highly recommend the Ford Expedition with HD towing package. The 3.5L Ecoboost is strong, combined with great gearing.