Montana requires a lawyer to register an LLC? All it takes in Michigan is a two page form and a few bucks. Then $25/yr, IIRC.
There are no special income tax filings for an LLC. Most single-member LLCs are pass-thru and the net profit that isn't retained earnings gets reported on the member's standard return. The only thing that would change that would be if you chose to file as an S-Corp ... which isn't that confusing, but is only worth the effort if your annual revenue is above a specific amount.
Worst case, you'd spend about $400-500 to have an accountant handle your taxes. Obviously, COLA in your state will affect that.
If you have dual residency with another state, I'm sure there are exceptions.