I guess this is where I chime in with my annual warning about the 507. I have been going up there at least monthly (during riding season anyway) since the late 90's as we have friends with a cottage on the 507. Now those same friends live full time at their cottage. It has always made for a great place to go for a ride, stop in for a visit etc. Since moving up to Peterborough almost 10yrs ago, it is only a 30 min ride to the 507 so I include it in many of my loops. While it is a very fun road, it is an unsafe one to be riding much over the posted speed limit. While there aren't any crossroads on the 507 there are many cottage roads and driveways shooting off of it. Since it is the only road to get to all those cottages, it is often busy with folks in a rush to get to the cottage, towing boats, ATV's, cars loaded to the roof etc. Every year the locals up there all take a guess at how many bikes will crash on the 507. It's not that they want riders to crash, it's that they know it is an inevitability. You get a lot of city riders itching for some curvy roads heading up there in droves every year, and since there are relatively few police in there area, they decide to do flex their bike's muscles. I've seen all manner of terrible riding on the 507 over the years. I've seen bikes passing over blind hills, I've seen passing on a double yellow, I've seen bikes passing way too many cars at once, I've seen bikes passing cars in the apex of corners! I've also seen the unmistakable skid marks of left by a bike tire that left the road into the ditch maybe a day before, or the signs of metal or plastic scraping off into the ditch and I've seen pieces of brightly coloured body work left behind in those ditches. Coming around some of those blind corners on the 507 I've been met with stalled vehicles, various items like coolers etc lying in the middle of the road, turkeys, a fox, racoons, and even a black bear sitting on the yellow line contemplating it's own existence! Seriously, it didn't move for like 5 mins.
The 507 is a fun road. Lots of great curves, but many riders don't give it the respect it deserves. I know part of the reason for it's rough shape is that halfway up you cross into a different county with a much smaller municipal budget, but honestly I don't think Peterborough county is very concerned with keeping their end of it up either. If it were all freshly repaved and smooth it would just attract more riders to flock to it every summer. If you are going to go to the 507 for a ride, and believe me, I'm not trying to tell you not to, you are best to head up mid-week. Much less traffic and much less chances of having a not-so-friendly chat with Johnny Law.