The Extend-A-Stay is designed for exactly your situation. Just buy a couple 30 or 40 lb cylinders to hook up and your good to go. When we're on longer term sites, we start out with the onboard LP tank full, and run off just the portable cylinders for the most part. If we happen to let both cylinders go dry, we can always switch to the main tank temporarily while we're getting the others refilled.
BTW, you might want to edit your profile to reflect your current Class A instead of your previous 5'ver. Putting that info in your signature can also be helpful when asking for related assistance or information.
