Congrats on a personal best-you are invincible! At least for today.

Several years ago 10 wheels recommended doing a 4 hour ride. That seemed way over the top for where I was as a rider. But I started taking a couple 4 hour rides a month. They were casual, ride an hour, take a break, ride another hour get a burger kinda rides. Then I graduated to ride 2 hours and get a burger then ride for a few more hours. If you can get your rear used to the saddle time and just ride, it is amazing how strength will follow. Shortly thereafter I rode a Century-highlight of my riding life! And I am almost 60.