Yea, did a project there a few years ago; fairly steep, heavily wooded river valley. From what UT2 recorded from AACo "Mike" (not comprehensive,) units participating were RID 5302 BCo "Cap"; RID 29503 HoCo "PM15"; RID 49024 "Fire Alarm 5"; RID 49141 "Comm 500." I didn't hear (i.e. record) any NRP units on Mike, but mention was made of "NRP 95" and Fire Alarm 5 seemed to hear him.
The closest tower sites to the Avalon area seems to be Brady Ave or Westview on BCo; Northern District or Blobs Park on AACo; Timbers on HoCo; and BWI, Rolling Road, or Waterloo on FIRST. The closest site on DNR's VHF system looks like Holofield. At one point, FA5 indicated that BCo was negative, HoCo "could get a signal into the system, but not readable." Not sure if that was an evaluation of the area in general, or a specific location. A coordinate was given in a grid system that was not the standard WGS84.