@Ryan Evans, if you have access to a well, I'd use it. A tiny house with running water would be more marketable than one without. Also remember to include the cost of putting in a road into the property if there isn't already one. Otherwise you'll have people getting stuck when it's rainy.
If you do the self-contained waste water, it will still need to be dumped. It's possible that you can get a port-a-potty company to come out with their truck and suction it out. Not sure if they can do that with RV waste. I looked into a holding tank like @Christen G. suggested, but in the end decided to go with a small septic system for our 3 tiny house RV hook-ups. You do get into a lot of regulations when it comes to waste water!
There are lots of tiny house enthusiasts out there, so be sure to call your place a tiny house, not a cabin. And if it's a tiny house, it needs to be cute and feature clever use of space. We've found that lots of folks aren't crazy about sleeping in a loft. Fortunately, one of our tiny houses has a bed that slides under the kitchen floor, with the bottom end sticking out to serve as a sofa during the day.
If you can make it all happen, it sounds like that would be a very marketable property!
Here are our 2 tiny houses:
www.airbnb.com/rooms/13248492
www.airbnb.com/rooms/14282082