chrisanddoctavia, you are going the right direction. In our park in Yuma, AZ. most motorhomers have installed the extenda-stay. There reasoning is for the pump truck to fill the motorhome, it is a 1.00 a gallon more delivered than filling their portable tanks at the pump dock. Also, they have to be on location when pump truck fills them. Your better off adding the portable tank and I wouldn't be to concerned about it walking away. Our two 30 pounders on our fiver are just behind a non-lockable bin door and they have never taken off.