Allan here from Sydney Australia. I am visiting Maine in August for a wedding. Travelling around and Portland is on the list on the way to the wedding. I know this is subjective question. Can anyone recommend where to stay that is central to everything? I cannot find a Neighbourhood guide. Is there one? I am looking to stay two nights.
I'd love to help, but I'm in Portland, OREGON rather than Maine. We were named after your destination but I don't know anything more about it than that.
If you Google "Portland Maine Downtown" you will find a website for the Portland Downtown District. There's a map that shows what is considered "downtown." Good luck!