FYI..anyone running across this discussion.
There appears to be another, "safer" detour option that's similar to that discussed above (Oldtown Rd to Malcolm Rd to Tunnel Hill Rd to Tunnel Hill Trail). This option was posted by a guy on the FB Gap group page. It gets off the C&O a couple miles earlier and takes a rural, gravel road to Oldtown Rd, then Oldtown for 500 feet to Malcolm Rd then continue Tunnel Hill Rd. He did a video of the route..may be used for some folks..