How about this...
- 14% of the teams are "away" teams at the Long Island Regional.
- 0% of the Michigan District teams are away teams.
In other words they aren't a local team in the sense that they live in a different area that is covered by a different "home" Regional.
If some of you are willing to take a shot at your own local Regionals, where you know who's just visiting and who always comes, I could do the remainder. It would be a coarse estimate across most of the events, since we have limited local knowledge, but it could be based on where teams consistently go over the past, say three years.