We could try to rig up your trees across the gorge somehow hopefully level enough to make a solid platform for the two 31" pieces.
I'm not sure how we would attach them to the trees safely though.
If the 20' span is too much, Btchn could probably bring out his electric saw to cut one down.
The problem with that is we cut these in a way that makes them structurely sound.
If we shorten them, they will be much weaker.
Also, the longer the spread, the higher and more unsafe it will be.
I say, before we start dragging 200/300 pound trees around, we try these as they are and see how they work.
Me and Btchn can pick them up easily; I don't think they weigh much more than 80-90 pounds each. If we stake them down, they won't go anywhere and we can move debris if we ever get another rain event like that again.
Since I have already cut my deck up, #14 is getting a bridge if it needs it or not.
That hill is tough enough to walk up; not having to go down and up another 10' would make a big difference.
Besides, we can drive it most of the way back there with minimal handling.