If you are going to get your license use Sea School. I went through them to get my license to run offshore Charter boats and they made things easy. I have heard that the CG classes are the hardest.
The other thing that you need to look into is Insurance, because now your boat is a business. You dont want someone getting hurt and coming after you. I do know a guide down in Flordia that makes all his clients sign a wavier stating pretty much that they are on a boat around water and slipping is possible, and that they are fishing and hooks are sharp, and he isnt responsible.
Good luck if you are looking into the guide thing....