Crossbreed, I loved bicycling! I space out however, and have wandered unawares (while on the bike ) into traffic, have been hit by car, hospitalized. No more biking. I'm challenged with paying attention/focus. I write forum posts in segments, keep coming back to it. Autistic inner world has some mighty strong pull!
Is there any way that your dog (Grim?) could keep you on track while bicycling? How about riding with someone on bike paths? It seems like a shame to have to give up something that you love to do.