[karussell]

For OSM-only data you could set up wheelchair routing with two commands (via GraphHopper) for the region of your choice:

https://github.com/graphhopper/graphhopper#installation

In the config you specify

graph.flag_encoders: wheelchair

and enable elevation:

graph.elevation.provider: srtm

It then considers elevation and many restrictions already but it is probably not as fine tuned as it should be. We would be happy to accept improvements.

[microcolonel]

I think you need a couple more things than that, like marking excessive cross-slopes, and having a better way to mark mid-way issues. The fields definitely exist, but there's not really a focused method of entering data like this, and it's not clear to me how to do this without messing up the presentation.