I just have a job that I go to. Nothing different then when I lived in a house or an apartment. The only difference is that now I don't pay any rent and can save way more money then I ever could before. It does help that I have a job that travels a lot. So as I write this I'm sitting in a comfortable hotel room with the AC blowing cold and the ability to take a long hot shower. But by tomorrow afternoon I'll be back in the van.
Not everyone that lives in a van is traveling. It seems like most on the forum do though. Most of what I read about boon docking and BLM land just doesn't apply to me. I'm pretty much always in a metropolitan city. Water is easy to come by. I go to the gym to shower most days. The only difference is living in a van as opposed to an apartment.
There are a lot of ways to live in a van/car/rv etc.. For anyone about to embark on this adventure I would say find what works for you. Try different things out. You could do seasonal work and save up some money and move on. You could also take a normal job and work for 6 months at that and save up as well. It really comes down to how you want to live.