I did exactly what you're suggesting last winter for about six weeks ... didn't want to winterize before taking a mid-winter trip, then winterize again. The plan worked just fine; only downside was the cost (my Oasis hydronic system burned a LOT of diesel in six weeks). I didn't have to use the AGS, as I could run an extension cord for 20 amps -- plenty of power to run the heat and keep the batteries up.
I did it because I hadn't winterized this coach myself before, and expected it to be harder than it was. This year I did, and found that it cost all of $25 or so for pink stuff and maybe an hour of my time. If I had last winter to do over again, I'd just winterize twice -- I spent much more on fuel.