Re: floating snack stand
The good news is that Maryland owns the river so you are only dealing with one State. The not so good news is that Maryland is one of, if not the strictest, States in the nations when it comes to the use of its waterways. Any application for a business permit would certainly involve approval from the Maryland EPA. When dealing with EPA be prepared to show up with deep pockets and spend a lot of time chasing your tail. Good luck.
A land-based business would be just as complicated. The Maryland side of the river is part of the C&O canal National Historical Park which means you'll have to get it past the National Park Service. Good luck with that one.
Once you get your operating permit from one of the above, you will need a Maryland business license. You apply in the county where the business will be operated. Count on jumping thru a few hoops since your not a Maryland resident.
Once you have your license, you will need to register with the Md. tax office for a tax ID number. If you plan to sell fishing tackle, you’ll need a federal tax ID number as well. You will be required to collect and pay the federal excise tax on any fishing tackle that you sell.
I can't see how this endeavor is worth pursuing. For the most part, the river is only navigable via small, flat bottomed boat, canoe and inner tube which limits the number of perspective customers to a select few. The limited customer base combined with the low profitably of resale products would have me pulling the plug before it got off the ground.
