Hi Jim,
Well, first take a look at
www.purvisbros.com/mars/marstop.htm if you have not already.
The town is still a town but is slowly being surrounded by suburban sprawl from Pittsburgh. It is easily accessed from Interstate 79 or the Pennsylvania Turnpike - their junction is about 5 miles from town.
We are friendly, no one has bitten any visitors for quite some time, and no other town has a cooler name. Let me know any specifics you might be looking for.
You may also get help planning a group visit from the local tourist promotion folks at
http://www.visitbutlercounty.com/joomla/
Mars - Out of this World!
Best regards,
Mac