I really like that you've planned core body strengthening. Most of us neglect that and it will really help you. Not sure that you need to do 3 days a week. Experiment and see how you recover from it.
Am I right in that you will be working up to riding 5 days a week? That would be good. Intensity in the form of intervals or hills is excellent variety. An easy recovery ride for me is 50-60 mins. Shorter doesn't seem to do much for me, maybe it is just my body.
What distances for your longer rides? If you can get to the point where you can ride a metric century a couple times a month with no soreness after you'll be in good shape for a century.
Those 10 week plans are really not overboard. You can plan your training based on surviving the century or really feeling strong. The more riding you do in preparation, the more fun you will have on your century.
I like your basic plan because it shows you understand that recovery is as important to your training as the actual riding.
Frends know gud humors when dey is hear it. ~ Da Crockydiles of ZZE.