bmcewan wrote:
My problem is, between the wife and I and a full tank of 26g of fuel, plus 50# of extra gear, and subtracting the 150# of driver weight (boy I wish I was back at 150#!) we're left with payload of 870 pounds.
Dialing in the tongue weight at 15% of trailer weight, I'm looking at a limit of 5800 pounds. 
Have I calculated this correctly? Any advice for fulltiming in something this light? I suspect the answer is "give up and buy a 3/4 ton truck." But would appreciate any help analyzing this and some advice on looking at the problem from people with more experience on this than I. Thanks!
The fuel weight should already be included same as that 150# driver.  Best to get a scale ticket.
If you trade skip the 3/4 and get 350/3500 srw as minimum.  Nothing wrong with a used gasser to save a few $$ upfront.
Consider renting a similar travel trailer before you buy and change your mind to go bigger.