budbon,
What year Vista. I have a 2011 Vista 27'. Mine has the dual slides. I loaded it with fuel (80G) and water 55G. With all my gear (and I have a lot)and the wife and I we weighed in at 16,400 lbs. 400 over capacity of the RV. The nice thing with my short Vista is it can tow well over 5,000lbs but you are limited to the receiver which is at 5,000lbs.
I would probably consider holding on to that Sammy for awhile, even if you do get a truck. That thing would tow nice behind a RV and can be fun to drive, consider it a toy.