Second gravel road encountered on way home. Second because the first would be too obvious what was going on. Crack it and start driving.
Hate to admit but we did this back in the days too. We also had a strict no solid waste rule in place for our bathroom so a little pee water and sink water is not going to really hurt anything IMO. We also parked ours between games at some places that were rural where could just pull it up and drain it in some grass or gravel area where it's not going to harm anything or along some gravel road in the middle of nowhere.
There just aren't many dump sites close to Ames unless you happen to be driving past one at a rest area on the way home or have access to a campground that won't charge you for just passing through. For as much as one has to pay to park in RV village would think that would be something for a future improvement there. I know someone that talked with Pollard when he was welcoming the first people there when it opened about how they should consider allowing people to rent pads during the week or through the offseason to generate a little more money. This person was waiting on their new house to be built and was already living out of their RV while between houses so though it would be convenient if they could pay to stay a few extra days since they weren't tied down to any location at the moment. The obvious answer at the time was no you need to be out on Sunday.
But this poses an opportunity if the athletics dept wanted to generate some additional revenue they could modify a few things there and charge to use the RV pads during the summer as there are all kinds of events that go through Ames that probably would have some demand for RV parking, have the golf course next door too that could see people wanting to camp out a few nights maybe to do some things in Ames, and then obviously have the days leading up to and after home games that maybe some would want to stay a bit longer. Would require some kind of management and reservation system but its an area of opportunity to have that area available for use outside of home games some too.