I recently picked up an ODC 816 (Creek Co) inflatable pontoon and have used it in warm water and moving water.
The first hurdle was car topping. It was somewhat wider (4' 6") than the rack on my Jeep Grand Cherokee. I solved that problem with a rack modification and it seems to work well. Strapping it down has become a snap too.

On my first trip on the Duck River I ran into a problem on the upstream return to the take out spot. First we were realy humping butt to beat a thunder storm! Row the slow sections and wade the shallow fast sections. About 100 yards from the landing I could make very little headway in a fast deep section! I made it to wadable water and had just about enough strength to tow it to shore, fortunatly it was close enough to the car that after a long rest I was able to get it loaded up for the trip home. (Keep in mind that I'm pushing 68 years old but not in too bad of shape!)
Because of this I'm adding a trolling motor just for this type of situation and am asking for advice/help from others that may have added trolling motors to their 'toon's. I have the kit from Creek Co. and a friend is going to loan me a trolling motor to try. I'm concerned about balancing the boat for the added weight in the stern. It does seem to be a little nose heavy now.

I think I tend to under inflate the boat and this may have enhanced the inability to row against the current! Just how hard to you make your pontoons? I've been using a Coleman re-chargable air pump and don't think it does the job, 2 strokes with a hand pump after the Coleman get it to where I can just dent it with my thumb! I do let it normalize in the cool water and add air but I think I need to do that with the hand pump.
Not much to be concerned about with altitude here, just intense sun.

Some of the most beautiful water I've ever seen is available here by boat only, the fishing is great but almost secondary. Drifting along the limestone cliffs of the rivers here is one of the most peaceful things I've ever experianced! The Trout and Blue Gills only add to it!

I did get babtised in the Duck last Saturday, but that is another story!