I have a LQS and two big box fabric stores not too far from me, and I still prefer to shop the internet. I can get what I need in a reasonable length of time, don't have to spend my gas to go and get it, can shop all the sales in the country, and the list goes on and on. Sure, you give up "petting" the fabric until you get it in your hands, but the other conveniences make up for that. And, in fact, I have shopped from so many stores online that I am mostly familiar with the quality of goods they offer before I buy. So the truck idea would be an idea...but there's a whole lot more to setting up a "store" than just that. And by no means am I trying to discourage you, just giving you a little heads up...
...good luck with whatever you decide!