Welcome to the tramplife. I've been on here for a year, but I mostly lurk and don't find the need to post often. I've spent a good amount of time both hitching and rubbertramping. There's a lot of really useful threads what you're asking in the Vandwelling/rubbertramping, and making a living sections. Gasjugging is a skill you'll definitely need to learn if you don't already know how to--the art of asking perfect strangers to buy you gas. It's easier than it sounds once you get over yourself. Took me about three months to do that, now it doesn't phase me. My line? "Hey, my name's Matt, I'm trying to get to (insert nearby city) for work and I ran out of gas, *hold up gasjug* could you spare a couple gallons to help me?" or, if I'm with a girl "My girlfriend/fiance and I are on our way to (insert nearby city) to see family, but we ran out of gas..." I don't think of it as lying, because it's not. MY work is busking and flying signs, MY family are my road family, which I see in every town. Smile and be friendly. Do it at truckstops, not small gas stations.
Until you get comfortable doing that you might try sitting nearby your vehicle with the can out looking sullen and/or doing something else (drawing, talking), or by the front of the gas station (this works especially at night when gasjugging sucks--I've had managers buy me gas). Within 30 minutes a good Samaritan will usually walk up and ask you if you need help. A lot of travelers refuse to pay for gas all together.
Fly a sign or busk to make money, it ain't hard. Pick up little jobs on Craigslist for a day if you have any skills. The Gigs section is good for that. Get yourself a camp stove and learn to cook, you'll save a lot of money on food and it will be healthier. Jump in dumpsters to feed yourself. ALDI is notorious for having full dumpsters of fresh produce. Rouses around Louisiana is also a goldmine. Not sure of other places, but check them all.
Sleep at rest stops. Pull all the seats out of your van except the front two captain chairs so you have room for storage/people/a bed/whatever.
That's my mini-rubbertramping guide. There's more beyond that, but you'll need to learn on your own. A lot of rubbertramps I've met are full of themselves and wield their vehicle ownership like a status symbol to lord over others. Don't do that. When I had a car I used it to help and feed others, always humble. Remember, this lifestyle is supposed to be fun and spiritually rewarding.
[edit]Also, pick up some tools and a repair manual for your van. Learn how to work on it. I can't tell you how important this is. Learn to change oil/fix radiator/replace starter and alternator/fuel pump/eventually how to change the transmission. If you stay on the road for a long time these things will all eventually fail on you. Change the oil more often than you would if you were living in a city--I usually did it every 2000-3000 miles.