The biggest problem with running for an owner first, in a van, is all the sitting you'll do in a van combined with making no money because you're splitting it with the owner. That right there can turn a lot of people off in a hurry. My advice would be to take $5000 to $8000 CASH and buy a good used van, then put a couple of grand (whatever) in maintenance into it to make sure it's road worthy (belts, hoses, any wear parts that haven't been replaced recently that are likely to go), and have about $5000 in the bank left over for emergencies and to live on while you're learning.
You run it, paid for, for a year or so as your trial-and-error van, while you learn how the income comes in and goes out, what you want to do and not do to your new van insofar as outfitting it for living in, and whether or not you want to stay in the business at all. If not, you're not out much, and you can keep and use the van or sell it. If you want to stay in the business you'll then have the knowledge and experience on how to minimize your mistakes that will be rather costly with a new van that you're making payments on. Mistakes made with a used but paid-for van are no big deal, but mistakes made with a new van take on a certain level of gravity that can pull you down. Even something as fundamental as how you outfit the van for living, a mistake with a used van that you're not going to keep for more than a year or two is a trial and error learning experience, but the same mistakes with a brand new van becomes an error that will try you, because the trial is over.
Meanwhile, you're banking money to put down on a new van a year later. If you can pay cash for a new one, or close to it, then you're that much ahead of the game from the start. The learning curve out here goes right through the wallet. You can flatten that curve a great deal if it doesn't have to go through a bank payment first.