What's a good site to pull down courses that can be used within PerfPRO Studio?RideWithGPS.com
is a pretty good site these days to do course extraction. MapMyRide isn't too bad either. You can search a course out pretty quickly then export it as a Garmin TCX file. The TCX files tend to be a bit more accurate, but the GPX format is pretty good too if that's your only option.
Once you have the TCX file loaded into Studio you may need to smooth out the gradients. This can be done for you within Studio to help reduce gradient chatter, which is important when riding a Wahoo KICKR. Too many gradient changes in a short time can overload the KICKR.