No worries! Halloween isn't really a holiday! All the stores are open, banks, businesses, and schools are open. Everyone goes to work or school and carries on just like any other "regular" day of the year. It won't be like some other holidays, like Labor Day or Veteran's Day, when schools or businesses may be closed, resulting in people taking long weekends and traveling. There's really nothing to celebrate, no reason to expect large crowds traveling, etc. You'll be fine.
Weather-wise, even this far north (I am about 250 miles north of Boston) we won't be worrying about snow... yet. It might be cold, but snow would be pretty rare (last time I remember snow on Halloween was in 1997). You'll be fine.