I'm younger than you. I had THR of left hip Oct 30, 2017. I was on my bike trainer 3 weeks post op. Rode a metric century on Christmas 2017 on trainer. Rode a full imperial century on Super Bowl sunday 2018 on the trainer a week before doing a century in Palm Springs as I was cleared to ride outside before SB sunday. I wanted to watch game and needed to see if I could ride that many miles so I combined riding with watching the game. I did the century:
https://www.strava.com/activities/1401602504 Not fast but not too bad. I was riding alone...no buddies to help keep me motivated thru the tough parts.
I trained for and rode AIDS/Lifecycle in June 2018 which is a 7 day ride from San Francisco to LA. I didn't ride every mile but I did really well. I did however tear my rotator cuff during the event.
I am so thankful I did the THR. I had anterior approach which made recovery easier as restrictions were not same as if you have posterior approach.