I too thought about and inquired into a LP hookup under the awning. When told it was an extra $110 for a hose one tosses under the rig, I didn't relish the thought of crawling under the rig to get the hose that is just out of reach, and cleaning dirt out of the connection.

It seemed like a simple matter of tapping off the cook top or water heater lines to an outside connection. Having ordered our PC and first RV two weeks ago, I contacted a more experienced RVer (Ron) who enlightened me with his usual sound reasoning.
I'll be carrying a few extra tanks when we tour this beautiful country. At about $3.50 per tank, you would have to go through 31.42857 tanks (4.02679 gallons) to reach the price of the hose. That doesn't sound like much, guess I should ask Ron how many tanks he goes through a year.
Besides, you could always sell one for a friendly profit to the guy whose eggs are half cooked. Or better yet, throw one in the campfire, or place some strategically around the perimeter shooting them with your rig defence S&W, to scare off the attacking Zombie hoards or grizzly bears!
