You didn't say in what part of PA you live, but I'm guessing that if Canada is close, you're probably near Erie.
East Coast RV Specialists has locations in Roaring Spring and Bedford PA
(about 16 miles and 45 miles south of Altoona, respectively). They carry Gulfstream towables.
http://www.eastcoastrvs.com
We bought our motor home from Martinsburg RV near Roaring Spring and they are now out of business. I believe East Coast picked up the Gulfstream franchise in the area when Martinsburg closed.