On an RV trip on the Oregon Trail, we stopped at a spring near (Marysville? KS?) that had a rock which was engraved by the Donner party. It was still clear as a bell.
Trail goes right by where I take my long hikes near Guernsey Wyo. along the Platte River. Wagon ruts are cut into solid rock. Must have been a lot of people come through there. Lucinda Rawlins grave is also near where I walk. She died of cholera after taking care of many who suffered and died from that fate. I must say it was a beautiful place to die.
We've been on part of the Trail in Wyo., but not through it all the way. Maybe next summer! Wyoming is a beautiful state.