Bill in Houston from Houston on 5/9/2019 1:40:22 PM:
Here's what I would do. Might be completely inappropriate for you. Evaluate your own ability and risk tolerance. Etc etc.
West of Case - use Google Maps satellite view. You can see where the bridge is probably out, and you can see an obvious ridearound.
https://goo.gl/maps/QZZiRNrQAngziDCr7
If the outage isn't there, I guess you're on 94 for a bit. Lots of flashing lights and orange vests for you and your crew so you can make sure that you are seen.
Steedman to Portland - Ride the Katy until you get to the actual outage. Backtrack a little until you get to a back road that you can take to 94. Ride 94 for as short a distance as possible, and then cut back to the trail on another back road. If I am reading the flood gauges right, that section isn't actually flooded. They just don't want people falling into a washout or getting caught in suddenly rising waters.
https://mostateparks.com/page/58843/potential-flood-locations
Any of the above could be a death trap. Evaluate on your own, and if it doesn't feel right, don't do it.