You could carry the pin wt of a loaded to 14-15K wt FW. However, from my experience, I'd not want to pull/tow much over 10K, with my 3.73 gears, for long distance use. If your truck has the 4.30 gears, I'd consider 12-13K actual loaded to camp wt.
Just to compare, my 250 door sticker is 3,232, and you likely have 4,XXX on your 350 door payload sticker.
You will like the towing of a FW, compared to a TT. You will like the ease of hookup with a FW. You will need to be more cautious of height. It will take a bit to learn the difference of backing a FW.
Jerry