We have a 2014 Tuscany with (presumably) the exact same system your Dad will be getting, and we love it. We're currently at the end of a weeklong trip in which we've used the AH to keep toasty at night, and for endless showers.
At campgrounds, we've just used the electric element at night, and it's been sufficient in relatively mild temperatures (50s at night). If it got a lot colder, we'd turn on the diesel burner. (Our AH only has one electric element, which is enough for light heating and basic hot water use, but not for showers or very cold nights.) We also have two heat pumps, which would also work for mild nights, but are much noisier.
For boondocking (or in our case, Wal-Mart stops between destinations) we run the diesel burner for heat. We seldom need to run the generator. Our house batteries and inverter are more than sufficient to handle our overnight needs, and recharge while driving. If our batteries are drawn down far enough, the AGS (automatic generator start) kicks in and takes care of the recharge. Note that this is in an all-electric coach, but as far as I can tell, the residential refrigerator is very efficient, so our overnight power needs are well-matched to our batteries and inverter. If we boondocked for multiple nights, I would run the generator long enough each day to recharge.
I can't say enough good things about Aqua-Hot, or hydronic heating systems in general. I do miss the Hurricane hydronic unit in my previous coach though, only because it had two electric heating elements and the "motor-aid"-type loop through the engine, which allowed us to heat the coach with waste heat from the engine while driving in the winter. Aqua-Hot has these features too, but not in the model I have now.
