Propane tanks...20 or 30 pounds??

You could go either way.. we ran a single 30 for a couple years. Switched to dual 20's later. It's all about how much cool weather boondocking you do. We spent 7 days out in late Nov a few years ago, highs in the 40's lows in the 20's, ran through most of the dual 20's. Would for sure have run out with the 30.

If you have a place to carry a third twenty pounder the economics and convenience win. Three twenties cost much less than two thirties due to the huge quantities if twenties used for BBQs etc. Also , exchanging twenties at small town convenience stores is an option but thirties are more scarce. Since you already have a twenty just add a dual tank rack and two more twenties. Use the third on the BBQ until you're ready for that long, cold trip. 

I have thought about going to a dual rack, but so far, have stuck with a single tank rack and carry a spare 20 lb tank. I swap them and fill the empty one at my earliest convenience so I will have it ready for the next swap. Since I bought the tanks with gauges, I have a relative idea of the tank level. The hot water method is still the most accurate inexpensive method I have found to get a reading though.

Originally posted by CharlieM The advantage of two bottles with an automatic switch over regulator is you don't have to switch tanks in the middle of a cold rainy night. Just wait 'till morning, remove the now totally empty bottle, and refill it. BTW, the new ultrasonic tank measuring devices work great. Convenient, no removing tanks to weigh, and can be used in place even when propane is not in use.

Very much agree, we won one at a rally last year. Works great. New rig carries 3 20's, but it's nice to check before a trip to see if I need to switch out and get one topped off.

This is the one I have. Works great.

https://www.amazon.com/s/ref=nb_sb_ss_i_3_15/146-2805682-4862748?url=search-alias%3Daps&field-keywords=dometic+propane+level+checker&sprefix=dometic+propane%2Caps%2C306&crid=210PHNI0MSNVU