Transient vendor across state lines

Greetings.I have been working on my hobby business on a very small scale the past few years, but this year I decided to start pursuing it more seriously. My husband and I met with an accountant and she helped me understand tax deductions and such. However, I am having difficulty determining what to do about vendor's licenses. Currently, as an Ohio resident, I have an Ohio transient vendor's license. Most of the shows I attend are in my home state, but I am going to want to expand into surrounding states soon.I know that each state has separate rules and requirements, but I can't figure out if I need a vendor's license for each state I intend to sell in. And do I need to register my business there too? If I register my name in Ohio, does that prevent people in other states from using it?Also, I am not sure at this point if I want to organize myself as a sole proprietor or an LLC, but I need to register my business name/DBA. If I do LLC, does that also include registering the name? I don't want to go through the effort of registering my name and then later decide to switch to LLC when I could've done LLC and that would have done the name registration.Any and all help provided would be very much appreciated. Thank you.-- Gwen