Welcome. I think you'll find mountainbikers are a friendly and fun group of people.
Good call getting a nice hardtail versus a low-end full suspension.
I live in Franklin, and ride Brown County and Southwestway Park most often.
Brown county definately has more miles of trail, but Southwestway is coming along with new trail being added by the week.
What size frame do you need? I've got an old Specialized I'd be willing to bring along as a loaner if need be. It's older, but shifts and brakes pretty well. It's a 17.5" frame.