While tank size is important, 35-40 gallons of fresh is a normal size and is sufficient for boondocking. I wouldn't worry to much about grey tank size for boondocking (we are talking boondocking not dry camping). If you are dry camping then grey water tank size becomes much more important. If you don't boondock more than a couple days at a time, don't want to be conservative and mostly stay in campgrounds, then 30 gallons is plenty of fresh water.
Lance, Artic Fox, Adventurer, Host, would be on my list of TC's to look at if you need a slide. If you decide you don't need a slide then add Wolf Creek, Northern Lite & Northstar to your list.