The Grant Pavillion is easy to reach from Interstate 255. Turn north on Telegraph Rd. which turns into Kingston then Broadway Avenue. At the transition from Broadway to Kingston is the North entrance to the Jefferson Barracks Park on the East side of the road. As you enter the North end of the Park stay to the right on Gregg Rd. and the Grant Pavillion is on the West side with a large parking lot around one mile from the turn onto Gregg Rd.
Kate Brehe willll send you a map if you get in touch with her (see below).