Hi, JD: We stayed here February 2015, so it's been quite awhile.
First, ask the Harris Ranch staff if you can run your generator, and find out if there's a "cut off" time when you'll need to shut it down. The Hotel is close by, so they may not allow generators. I don't know as we didn't use ours. Always ask.
Second, because their parking lot is often used as an over-nighter for weary travelers, if there are other rigs/RVs parked near you, please check with your "neighbors" before you run your generator. Let them know for how long you will run it.
Don't be surprised if they request you not run it. Although this is a beautiful facility, many stop and stay here to get some much-needed sleep in this fairly quiet area.