Preparing for a metric century
On August 10th I am hoping to ride in a local metric century (100 km). I've gotten back into cycling this last month and have been using a road bike. Is there any particular method I should use to prepare for this? I'm in generally good shape, I favor weightlifting more than cardio but I'm capable of decent endurance compared to the average couch potato. I've been putting in time on both the roads and trainer. I can do shorter rides at a decent pace, example a 25 km round trip in just under an hour with just a 30 second break for water other than the quick breaks at stop lights and some light coasting. I've also done longer rides of 40-50 km round trip with a couple breaks of 5 mins or so. I am somewhat heavy for a cyclist (188lbs currently) but am shedding a little weight and expect to be in the low 180s by the time the ride happens.
Are there certain benchmarks I should be trying to hit over the next two months? Is there an ideal length of ride to help me reach this level of endurance? Should I avoid challenging rides for a couple days before the big ride?