My DW and I rode a 100K today. First ride over 40 miles for us since starting riding last August after more than 20 years absence. I'm really proud of her effort since I doubt that she has put on 1000 miles with very little climbing. The 100 K had about 2700 ft. of climbing, the 100 mi considerably more and I know she was hurting at the end.
Beautiful day for a ride. Started at about 60 degrees, probably high 70's at the very end. Bright sunshine and very little wind. The ride (Tierra Bella in Gilroy, CA) limits to 2000 riders and I'm sure they sell out every year. The Almaden Cycle Touring Club (ACTC) organizes the ride and does a superb job. Roads for the most part are not heavily trafficed. I'd certainly recommend this for anyone within striking distance of the San Francisco bay area.
My arms and my seat got a bit sore, but I think I'm within striking distance of riding a Century, maybe 3-4 months. I've got my eye on an unsupported ride that looks really interesting