I looked at that, and there are a few things I would consider doing as upgrades.
Adding an accumulator tank like a Shurflo 182-200. This helps, as last time I checked, the water pump is a fixed speed, so the water pump short-cycles less when taking a shower.
Adding a spare tire, like mentioned above.
I wish I knew a way to deal with the trim, because on that model, as it doesn't have a fiberglass front to protect it from driving water, if something isn't done, cabover water intrusion is practically guarenteed. Eternabond tape comes to mind, although that is ugly.
