Her post kind of got buried below, plus she added some additional budget details and things, so here's what she's looking for:
$20,000 budget for reception
150-175 guests
in or close to Pittsburgh (Murrysville/Delmont/etc. area preferred)
rustic/farm look
Her date is 9/10/11, a Friday
Here's what has already been suggested or looked into:
Frick
Gateway Clipper
Phipps
Lingrow (over budget)
Schenley Park
Heinz Field
Armstrong Farms
Grand Concourse
Springwood (didn't include much for 20k)
Mayernik (books up fast, so call them soon, astra, if you want them)
I'm suggesting Pittsburgh Center for the Arts in Shadyside near Mellon Park.
Also, what about the Aviary? That has a natural feel to it, but not sure how many it can hold.
You should definitely be able to get under 20k on a Friday for 175 people!