To get to Rocky Top from the Valley, take Hwy 22 in Marion County east past Gates, OR to Niagara Hts. Rd, across from Niagra Park at the intersection with the red and white waterwheel, well-known to area residents and weekend travelers to Central Oregon. Watch out, the left turn approaches fast as you round the corner and I still miss it despite having been up there several times.
UPDATE - K7AHR decided to check the ground conditions for these two peaks. Both are apparently accessible with the usual cautions regarding hiking in burn zones.
Hearing that the Big Hollow TH is again open, I began making plans to activate Timbered Peak and Sister Rocks (W7W/LC-064). Unfortunately, a BARC map (dated September 30, 2020) indicates that Timbered Peak was severely damaged in the Big Hollow fire. At this time, there appears to be no way to safely access either summit. More below...