Hi Gowfermike, I notice from your profile that, like me, you're in the wrong half of your 50's. I had my knee reconstruction (ACL) about ten years ago and I was on a walking stick / off the bike for about six weeks. To redevelop enough knee condition to do multiple consecutive 50 mile days would have taken me many months, possibly close to a year (then again I had some complications). Add another ten years in age and recovery is likely to be slower. But as Wogsterca accurately says, it depends on your pre op condition and your post op recovery regime. My guess is that absolute best case is that it would be at least six months before you'd be in a position to give it a try -- and travelling ultra light, preferably with sag support, would be advisable.