After quitting my job I did some consulting (writing code for Engineering companies) under my own name.

I was living in New Hampshire at the time. Eventually I formed a LLC in NH for the purpose of selling software I was developing, unrelated to the previous consulting jobs. Soon after formation I moved to Massachusetts. I did more consulting under my own name for local clients. In order to do business in Massachusetts with the LLC from NH I would have to jump through hoops and pay money, not to mention the confusing (for me) tax situation. So I kept the consulting under my name but used the company name to represent the software I was working on. I don't yet have any sales of that software so I didn't have to pay any taxes and just put the LLC as a disregarded entity when filing taxes, even though I do have a taxpayer ID for it.

Moving forward, I am not sure if selling the software will ever happen. I'd like to do business in Massachusetts as a more formal entity. I'm thinking maybe I should consolidate the software I am trying to sell and any consulting based on that platform with the consulting on unrelated issues. Not sure if there are any IP issues if I write software owned by customers and software owned by me under the same business entity.

I don't want to have to worry about paying / filing for income taxes in both NH and MA.

What's the best way to do business of software consulting and software sales in Massachusetts:

-Get permission to do business in MA with my NH LLC and do consulting under that entity as well as potentially sell the software I am developing and associated services.

-Start an new LLC (or maybe Corp) in MA and roll everything, sales and consulting, under that.

-Keep things the way they are, that is, attempt to market the software and associated services under the NH LLC, and consult on unrelated topics under my own name.

-Start yet an other LLC (or Corp) in MA just for consulting without any IP on the stuff I make, and keep the NH LLC for software sales.