It is not just about federal taxes.
Depending on where you are conducting your business you will need to collect sales taxes and deliver them to the state and local governments. In many states you will also need to pay business taxes. Similarly, you will certainly be responsible for paying use taxes if you buy anything from another state (like fuel on a cross country trip).
I strongly urge you to find a good accountant and/or lawyer to help you set up your business so you are in concert with federal, state, and local laws. If you try to save money by "Keeping it simple" you will be likely to face a huge tax bill along with penalties when the state catches up with you.
Your business plan is the most important part of setting up your business. Without this you may well go through all the motions of being in business but lose money on everything you do. The same fate, or worse, can result from not properly working out your cash flow (a core part of your business plan). Another part of your business plan is to identify who your customers are and how to acquire them.
You really need to think about what you are doing as more than just a tax exercise.
Paul
Camas, WA