Dry camping is not that difficult. For me, that's pretty much all I do. Here are my tricks:
1. Only turn on lights when I need them. The inside lights do not need to be on if I'm sitting outside.
2. When it's convenient, use the campground bathroom facilities. During the day, it's not a terrible thing to walk a bit through the campground to use the bathrooms. At night, etc., use your RV facilities.
3. Try the campground water. Usually, it's pretty decent water (unlike RV Park water). You can use it for cooking, coffee, etc. That reduces your use of the fresh tank water.
3. Simplify. People have lived for centuries without a microwave or hair dryer. It's not that difficult to get back to that world. Use your power for necessities and skip the conveniences.
As for ruining the trip, my first camping trip with my TT, I discovered a crack in the hot water tank (so no TT water at all) and my battery wouldn't hold a charge (so no electrical). I had a great time. Lanterns, flashlights and LED puck lights covered lighting needs, propane covered cooking and fridge, and the campground water spigot covered my water needs. Sure it would have been more convenient had those things worked in the TT - but it didn't make it impossible to stay for the duration and enjoy my trip.