Done that for 2 1/2 years.
Monthly rate for RVs in Lot B is $30. Your airline might reimburse you.
Constant, free shuttle service from the lot to the terminal.
Climate year round is camper friendly - not to cold, not to hot.
Safe - some 'campers' are Airport Police, TSA, Airline folks.

Airport tried to bann all RV parking a while ago but some United Mechanics have managed to work something out. Contact them (I'll try to find a phone number for you - but can't promise)
AA and AE employees have their own RV parking at the former TWA lot.

About 2 miles away is a RV lot at the beach - dump tanks and get fresh water for $5. Dockweiler or something like that.

For what you pay for a crashpad you can pay off a RV - and it is tax deductable.

Good Luck - I wish I could hang out in my RV at the beach and not sit in an expensive pad in NY.