I have chronic spinal issues and love riding bikes. Personally, I would not even attempt to do that. But I have had 4 surgeries and have numerous discs that are not in very good shape. I do get sore knees with a lot of clicking and creaking, so I would not subject them to that abuse either. I have no idea what shape your body is in, but in reality, only you can decide. Anyone you could borrow a bike from to give the single track a try? If yes, I would try that on relatively low impact single track to see how you feel. Progress from there if all is good.