The real problem was when the valve that let fresh water in got stuck open. The only solution then was to shut off the water to the trailer. The next day I learned a lot about RV toilets. Not having running water will give me inspiration to fix things. I learned all about the valve that was broken and probably could have replaced it easily. For just a few dollars more I could buy a whole new toilet, and in reality the job to replace the toilet was no harder (or grosser) than to replace the valve. Then I found the RV toilet of my dreams. I'm 25 now, and never did I think in the whole of my entire life would I be buying a toilet. Much less refer to it as the toilet of my dreams, but when I saw the Dometic Sealand 210 Standard Height model I knew that was the toilet for me.
For the record, anyone in the market for a new RV toilet, I highly recommend Dometic. In reality they're all good brands. The AquaMagic I replaced did last for 20+ years. The ease of installation, and the fact it's one of the few RV toilets made of porcelain, make this a toilet I'd recommend to all my full time RV friends. Also this escapade has tempted me to put "master plumber" on my resume.
It was a nasty job, but over all not nearly as bad as I thought. I psychologically prepared for a full 24 hours before removing the old toilet. I was surprised with how standardized all the different brands of all the different components of travel trailers really are. On top of that, how little the basics of it all have changed over the years. A RV toilet from a 1966 Airstream works and mounts just like the one that came with my 1982 Airstream. Then my 2005 dream toilet here mounts exactly the same. That's some incredible engineering that started way back in the early says of the travel trailer.