I like Bruceper's idea. I'd go for a unit with low mileage so as to hopefully avoid any major mechanical issues. I'd be fine with two house batteries if moving every two or three days. You have to empty tanks and get water etc. anyway. Booster's suggestion to plug in once a week or so is good advice.
You might be able to get a near new unit with your budget though.
I took a quick look on Autotrader turned up 2012 Roadtrek 190P with solar and only 7,000 kms, yes kilometers. It's a bit over your budget but not so much that a max offer of $70k would offend anyone. It probably has two house batteries and would have an inverter. It was out West though.
The Roadtrek 190P has a nice exterior storage compartment and lots of interior storage.
You also could get a very nice unit for much less if you are patient but can also act quickly.
Your question - What would you buy with $70K?
- is a tough one for me to answer as I'd look for something costing less than that that has low mileage and was demonstrably well cared for. No rust.
A brand new Safari Condo Promaster Flex starting price is CDN $88,530. I like that layout and would probably opt for rear twin beds. GeorgeB posted photos here: http://www.classbforum.com/phpBB2/vi...tart=44#p25721
Start visiting all the dealer lots near you and get inside the units to get an idea of the different floor plans. You might find that you have a strong preference for one over others. That would help narrow down the search.