I think you've got an idea that is very "geographically" centered. I would not need you where I live in Oregon but where my sister lives in Eastern Washington and sister in law in Montana, they would flock to your truck. At one time I did see a website that had an old school bus fixed up as a fabric shop. He/she went from town to town on the east coast and sold fabric and also did quilt workshops etc. So the guild or quilt group would sign up and have the owner drive into town, set up the bus shop and teach a class at the local community center, grange or whatever. I loved the idea! What a great adventure. Just think of the places you would see and the people you would meet! Also you have a build in resource here at this board. Write up a great business plan (Do you have someone who can help you do this?), do your research and good luck!