A lawyer can best answer your questions. And you are well ahead if you talk to a lawyer first. Saves a lot of hassle later.
I’ve set up two business - one was consulting. I did work for companies in other states and it was never an issue. (The other states were California and Georgia - I’m in Texas).
(Second business was for my son - it’s his business, I just helped him set it up)
I used Quick Books to manage the financial side of the business and that was a learning experience.
Good luck - it can be a great experience.
Thanks! The financial side of the business is something I’m less concerned about, since I have a lot of experience in that area. One of my peculiar characteristics as an engineer is that I seem to know more about tax law and business finances than the people who do my taxes.