Two things important to completely a century in good shape and feeling well are preparation and eating/hydrating. My advice is build up to at least 65 mile rides in advance; ideally 75 milers. Do a long ride and the weekend and keep increasing the distance until 65 feels okay. The other is keep your hydration and energy/fuel level in good shape and eating and drinking throughout. Your plan looks good except I would stop at 20 miles instead of 40 and not skip any. After you get one or two under your belt, your experience will tell you what works for you and what doesn't.