Thanks all for the advice and encouragement.
Yesterday we planned on riding 60 miles. My friend mapped a route that was actually 65. We took our time, drank and ate frequently, made a few short stops for bathroom and snacks. With a wrong turn at the end we ended up doing 70 miles with 2500' ascent at an avg of 14.3 mph. Where was some decent wind and several difficult (for us) 8-9% hills. At end we were tired but generally felt pretty good. We plan on tackling the 100 miles.
The ride is in 2 weeks. Any advice for next weekend and the week prior to the ride? Do we take it easy, maybe a 30-40 mile ride next weekend, and few short rides during the week?