Hi!
First, I think you would need to define what a full timer is. It sounds straight forward, but there are differing notions of what that entails. For instance, will you maintain a permanent residence while on the road? That adds a level of complexity and expense that makes the answer more complicated than it needs to be.
Alea and I recently decided that we will become full timers around Sept 2015. For us that means selling our house and rental property, and selling pretty much everything else (storing only irreplaceables - a few albums, some original art, the chest built by her great grandfather 125 years ago). We're hoping it will all fit in a 5x5 storage unit, but even that can cost $500 or more per year to maintain.
I met Alea while on a two year bicycle tour nearly 30 years ago. I loved that lifestyle - you knew where all of your possessions were and everything was within arms reach. The longer you were on the road, the less you carried, and life quickly got down to its essence. We'd love to do that again, but neither of us is interested in hauling gear and sleeping on the ground in the snow and rain, plus we have a dog, and I'm NOT going to be the one to pedal her around.
Part of our solution to being full timers will be a new Ford Transit Connect Cargo Van. The long wheelbase version will allow us to keep both of our bikes stored inside on Yakima Highroller bike racks bolted to the floor (out of the elements and hidden from thieves). It has a ton of space for gear, so we plan on blocking off the curbside door with a flat panel tv (with Bluetooth headphones so we don't disturb the neighbors), which will be part of our outdoor living room. The TV will actually be our PC Monitor, so the main use will be for things that our netbooks aren't so good at, as well as playing exercise videos, the occasional Redbox rental and OTA TV when we are within range of a station. Our plan is a series of tag-team bicycle tours throughout North America: I'll ride one day, while she and the dog drive to the campground, shop, plan meals, etc; the next day we'd reverse our roles.
Some key things to consider include: where to have your mail sent and how to get it forwarded, and your communications and internet access on the road. Some folks will have relatives to accumulate and forward mail for them (I did that while cycling through Europe, though one time my nephew dropped the ball and I had to scrape by for a week before the mail [and the traveller's checks] finally showed up). Some RV clubs also offer such services. The most straight forward option appears to be the UPS Store - you get a street address that you can use to establish residence for tax purposes (think of the half dozen or so states with no income tax), and their stores are just about everywhere.
For communications, to me the phone is the least useful technical gadget ever invented, but I'll have a simple pay-as-you-go cellphone for the rare times when a phone really is indispensable. We're thinking of going with Virgin Mobile's Broadband2Go MiFi so that we can have secure wifi on the road, at least when there is cell coverage.
Getting back to your original post, if you live a wash and wear lifestyle you'll thrive on the simplicity of living in a teardrop. If you have poofed up hair and a daily make up routine you'll quickly be longing for a castle-on-wheels with an adequate "throne room" (after all, the big rigs are basically mobile toilets with limitless optional add-ons). In short, ask yourself how you compare to Goldilocks? Does everything have to be just right, or is it OK that sometimes it's too dry, sometimes too wet, sometimes too hot and humid, sometimes too cold and windy? Goldilocks lives in a Glamper to make sure everything is just right. People who are happy living a simple life (by choice) live happily in teardrops.
-Steve