surfnturf,
Ditto what previous posters have said. I think you're getting some solid advice here. I would just add the following notes from our personal experience with our Silver Kitten (YMMV):
1) Even with a modest suspension and body lift and a low-profile roof rack, a pop-top 4X4 Ford E350 can easily go through the drive-thru line at your favorite fast-food joint, but most of the "tall boys" can't. There's often a 9-foot height limit, so you might want to check the sign on the banger-bar above the drive-thru line at your favorite burger joint. Keeping a low profile is one of the advantages of the pop-top penthouse. Sometimes this lower profile also increases your parking spot options when you're going for a mountain-bike ride or just camping among the trees.
2) With ordinary care, the International 7.3L engine that Ford used in E-350s is generally rated for about 300,000 miles between rebuilds, so you might want to remain open-minded about the older and higher-mileage E-350 Sportsmobiles with this engine. This could greatly reduce your initial cost, as Twoxentrix suggested, leaving you with plenty of budget room to renew and upgrade a new-to-you SMB into something that's just the way you like it. We got our used 2002 SMB several years ago for much less than $70K with about 150K miles on her. Even if you bought something brand-new, some modifications and upgrades would still be inevitable. It's just part of the SMB/VanLife "disease" that we all share and enjoy!
3) SoCal gas IS expensive, but with the better fuel economy and (sometimes) lower per-gallon cost of diesels, the resulting cost-per-mile suggests that any diesel-engined purchase options you have available should not be ignored. Also, I really like the effects of running high-cetane diesel fuel, either through the use of fuel additives, or getting the "renewable" diesel that is available from Unocal and sometimes ARCO stations. (It quiets the diesel "clatter" significantly, in case that's an issue for you.)
4) If you buy a van that's already been made into an RV (i.e. a Class-B motorhome), the insurance rates are much lower for "motorhomes" than for regular vans, because the insurance companies assume (often quite correctly) that you will not drive them as much, and therefore their exposure to risk will be much less. Just be sure that the RV you buy has the minimum requisites (i.e. at least four items from the list below):
From the California DMV website:
https://www.dmv.ca.gov/portal/handbo...r%20occupancy.
The important part of the above link is shown below:
"Motorhomes must contain permanently-installed independent life support systems which meet the criteria of the American National Standard Institute (ANSI) and provide at least
four of the following facilities: cooking, refrigeration or ice box, self-contained toilet, heating and/or air conditioning, a portable water supply system including a faucet and sink, a separate 110 to 125 volt electrical power supply and/or liquid petroleum (LP) gas supply. Van campers do not contain the permanently-installed independent life support systems identified by the ANSI for motorhomes." [emphasis added]
5) Everything breaks or wears out sooner or later, so don't forget to consider the availability of dealer-only parts and auto-parts-store parts for whatever you decide to buy. There are others on this forum who might be able to advise you of their experiences in trying to get MB Sprinter parts while "on the road". (I've heard some horror stories.)
Hopefully at least some of the above will be of help in your decision process . . .
Timerider