what to look for in a used 13-14' poptop
3 ways are great IF set up well. Mine honks in summer heat. You can easily clean the ruby jet and flue, insulate and vent it properly and you are there. A PC fan or 2 placed strategically will just help it along nicely. Use very little LPG. Only 12 volt when connected to the truck. I recommend a fridge switch and also running heavy cable to an Anderson plug with a heavy feed at the rear of the truck. I went from 10.5 v on at the back of the fridge to high 12's when on by doing that.
Cheers