An issue I would have would be storage unless you have a truck/van that can double as a storage unit. Loading and unloading fabric is a heavy job too. I can see outdoor markets as having a lot of traffic, but you need to be able to protect the fabric from the elements. In our climate selling out of a truck in the summer would require air conditioning. I think a major concern would be the cost of a permit for selling in every community and the safety/liability insurance issues with people climbing in and out of a truck. One positive is that if people want to see th color of a fabric in true light, they wouldn't have to go far to get outside.
Dayle