EdAA from Ann Arbor on 10/29/2021 5:32:45 PM:
In case others are looking at this thread to decide how to navigate around this, I'll throw in another data point. As always, your mileage may vary.
My wife and I dealt with the bypass on October 17th, on the 5th of our 8 day journey from Pittsburgh to DC. The 17th was sunny, but the trail had a few wet spots from the rain the day before.
For calibration, my wife and I are in our 60s, and are in pretty good shape. (My wife had a knee replacement a little over a year ago.) We like to hike as well as bike, so climbing a hill is well within our comfort zone, at least without having to push a bike. Our biking is only on paved and dirt roads - we are not even remotely mountain bikers.
It took us about an hour to complete the bypass. We walked the entire way, and weren't in a rush so we'd stop to read historical signs, enjoy views, etc. We changed into walking shoes (sneakers) before starting. I also put the shoulder straps on my panniers and carried them (about 35 pounds) on my back rather than on the bike, since pushing the (top)heavy bike uphill with my arms stretched out enough that my legs didn't bang into the panniers was awkward and tiring. I put my wife's smaller and lighter (10-15 pounds) panniers on my bike, so she only had to push the weight of her bike. With a couple of breaks to enjoy the view we got to the top in about 25 minutes.
At the top, I put my panniers back on my bike, and carried my wife's instead, since the panniers don't get in the way much when walking the bike downhill. As mentioned by others, the path downhill (heading towards DC) is a rarely-used dirt road, so if you've got the right bike and practice you probably could ride it (at least after the initial steep part). On my 20-year-old Trek with smooth 35mm tires I didn't think it was worth the risk.
All in all, it was much easier than we had feared it might be, given the mixed messages we'd seen online about it. Even the NPS says to allow 1.5 to 2.5 hours to do it, which had us nervous since we feared we'd be more likely to be among the slower people attempting it.
One last thing: As we were considering our alternatives, we were put in touch with a man named Dan who runs a B&B in Paw Paw (WV), and who can shuttle riders around the tunnel. The price he quoted us was $30 per person to take you from about 1.5 miles before the tunnel (Sulphur Springs Rd) to the crest of the bypass path at Tunnel Hill Rd, or $60 to take you all the way to Little Orleans. We spoke to him, and he convinced us that we'd be fine on our own ... super nice and helpful guy!