Cancel? I hate being negative, but sometimes our bodies and/or lives just can't conform to our goals. If 27 miles is kicking your hiney two weeks out and your training time and energy is limited, I just don't know how ready you can realistically be for a metric on June 2nd. I did the century a few years ago at the Harpeth River Ride. I don't remember it being crazy hilly, but it was hot, and that can really take it out of you if you're not used to it. Beside canceling, if you can get your training rides up to the 50-mile mark, you might be able to gut it out. But do you want to? If the answer is "not really," then politely tell your riding partner that this isn't your year and that you're sorry. It happens. I did the ride alone and spent a lovely weekend by myself in Franklin, so maybe your friend can still salvage the weekend. Or perhaps you can do the shorter route while your friend does the metric. Good luck with whatever you decide.