My family and I just returned from a 12-day, counter-clockwise tour on the IDHSMBR main route. I thought others may benefit from our experiences on the washed out Featherville to Ketchum (FR227) portion.
In short, we continued on the main route (FR227) and made it through the rock slides and washouts. It was not easy, but not impossible either. We decided to push straight through rather than use either of the proposed detours. We did not want to add the significant elevation gain and tricky single track of the Skeleton Creek / Fleck Summit detour, nor did we want to take the highways up and around through Pine and Fairfield.
There were three difficult areas as we pushed through on FR227: the two big rock slides at about 16 and 17 miles from Featherville, and then the big washout caused by Big Smoky Creek taking over the road at about 25 miles from Featherville (near Bowns Campground, at the junction of Fleck Summit Road and FR227. Note: Bowns CG is not on the IDHSMBR map). There were also a couple of other areas where we had to walk through the creek to reach the road on the other side, but these were minor in difficulty, by comparison.
We found the big rock slides manageable. The trail built by the forest service was passable, even with loaded bikes. My girls (age 20 and 17) were able to carry/push their bikes through these two trails. The first rock slide took us about 40 minutes to cross, the second took us about 30 minutes to cross. The first was 0.3 miles long, the second rock slide trail was 0.2 miles long. The videos posted on YouTube by PDiddy were fairly accurate as to the difficulty and passability of the rock slides. After getting across these two slides, we were able to ride for several miles on what's left of FR227.
Our most difficulty was with the big washout caused by Big Smoky creek near Bowns Campground. It is possible that we didn't find the correct trail around this washout, but we tried several options before getting blocked by undergrowth and deciding to ford the creek. We ended up crossing the creek multiple times as we looked for the correct trail. I was carrying bikes and gear, back and forth, since my girls couldn't cross with their bikes... The water was still too deep and swift for them to do anything more than get themselves across safely. In places the creek was about 3 feet deep and fast, making crossing with gear tricky, but not impossible. I didn't fall, but almost did while carrying bikes and gear overhead (for the record, I'm a reasonably fit 45 year old male, 6 ft. tall).
All in all, it took us about 4.5 hours to get from the road closure sign after Baumgartner to Bowns Campground. We spent that night at Worswick Hot Springs and then tackled Dollarhide the next day. Dollarhide was an amazing ride and shouldn't be missed.
Our advice: the FR227 route should be done only by strong mountain bikers who are lightly loaded (bikepacking style) and are willing and able to carry their bikes and gear. The same may be true for the Skeleton Cr/ Fleck Summit detour, but we cannot say for sure since we didn't go that route. Based on other's descriptions, that detour sounds like advanced mountain biking with significant elevation gain.
If IDHSMBR riders are heavily loaded and are not willing to carry their bikes and gear over rocks and through water, then the big detour on the roads through Pine and Fairfield may be the best option for them.
I'll try to post some pictures of us crossing the rocks and through the water - the forum doesn't seem to allow me to post them with this message. I would also be happy to answer any questions others may have about our trip and what we encountered.