I don't have propane on my truck, but just wanted to point out it is the "Week of May Madness" and also a few other "get togethers". So Don't get too upset if you don't get many replies until Monday. Just something to think about... .
If it were me I would get the horizontal forklift propane tank, they are 45 or 50lbs capacity, I can't remember. I used to fill them all the time when I worked for CAT (lift truck division).