Doug.. You are mostly correct. Medix Grade Rd. is at the end of Shagger's Inn Rd. coming from the dam. There is no bridge to cross unless you turn left at the end of Shagger's Inn Rd. and take (Medix) Grade Rd. down to Medix Run(the trout stream). This is known as Huntley. To go to the gates, turn right on Grade Rd. at the end of Shagger's Inn Rd, and proceed upgrade. You will hit the first gate shortly after passing the gray camp onthe left. The gates are not closed, and are marked with lots of orange surveyor's tape. The upper gate is about 1/4 mi. on up the road. I saw no signs of any sort with the exception of the "Posted" signs on the trees betwwen the gates. These signs have been there for years. The survey stakes and the gates are the only new things I noticed.
Will be very interested to hear what you find out.