YetiandtheSherpa said:
1.) I am 6'2. Is it a must to have a high top or an extended van?
Well, no, of course not. Some of us live in cars. Ultralight backpackers live in 1 to 1.5 man tents. You're not going to be spending your life in your van, it's mainly for sleeping. You want to make sure you can sit down comfortably somehow, to do things like read a book or work with a laptop when the weather is too cold / windy / annoying to do it outside. In my car, that just means I throw a sleeping bag or bag of laundry behind my back, and sit up in the area that I otherwise would sleep. Works fine. Very rarely it gets a hassle from a cop, but it works fine.
Consider that you could be in a bunk bed on a ship, or a submarine, or living on an Arctic research station, or on the International Space Station. That might put "space you need" into perspective. Some people in Tokyo sleep in "coffins" that they rent by the hour.
4.) Realistic budget? (5k for the van plus mods if need)
Couldn't tell you about van costs. My car cost me $100 once upon a time. Put a new battery in it, ran fine for 1.5 years without me doing a thing to it. Didn't even change the oil or antifreeze, I was such a dunce. How well something will run, based on what you paid for it, is pretty random. Eventually I learned how to fix cars, so that car of mine is still my daily driver.
5.) Power options, converters, etc...
A power inverter is useful
if you have a deep cycle battery to go with it. If you have a Starter Light Ignition battery, aka standard battery that everyone has in a car if they don't know any better, it is not designed to draw power for very long. You can easily kill it if you try to run your laptop off a power inverter. It is better to find electrical outlets in civilization. If you're not in civilization, since you're doing a van you could try the solar panel route. I've got a car and I've thought the panels were too expensive and bulky to deal with. Electricity in the woods is one of my great unsolved problems. I just switched to urban camping mostly.
Do I need a fridge? I plan to have lots of canned foods and dry foods.
No, you need a cooler. I've been using a Coleman 6-day cooler for 4 years now. It's big and takes up my front passenger seat. To go
everywhere, like the middle of National Forests, I would not trade it in. If I was going to do exclusively urban camping, and knew I'd always be near grocery stores, I might trade it in for something smaller. It's still plenty useful having large capacity in an urban setting though. I might get yogurt on sale for $0.49/lb. or something and live on that for a month. Happened last summer in Asheville, there are closeout grocery stores up there.
You can do canned food but don't get too addicted to it, for health reasons. Can linings have Bisphenol-A (BPA) which is an endocrine disruptor. Even small amounts will do bad things to you over time. Nowadays the only reason I do cans is when it's too cold for me to want to bother with cooking. Then I look for canned beans that don't have weird preservatives. Black beans seem to be the ticket, others have EDTA "to preserve color". Stoopid. (Heh, this site blocks the word "stupid". Because the software is stoopid. ;-)