We are pretty new to RVing and have concluded a Calif/Colorado loop recently. So far, the main lesson I have learned, I think, is to avoid RV parks and dry camp in parking lots. Having a 24' Mallard trailer, our two main limitations are no generator and a smallish (40G?) gray water tank. Is it feasible to install a larger gray tank? Has anyone here ever done such a project? I tried to view the underside of the trailer, but it's pretty well sealed with netting of some kind. Am I nuts to want to stay in consenting owners' parking lots such as walmart? Thanks for any comments or suggestions.