I'd say as a rough guesstimate about 90% of my recently achieved R 100,000 was done by riding defunct Calendar events over a 14 year period, some of those rides still exist as perms, which I have done many times, but those rides were designed in the 1980's based on roads you wouldn't want to use these days, obviously you have to agree with your DIY organiser which route you take etc by using the Google maps distance thing, basically like the old 'mesh' they are a guide, you will in some cases need to go a tiny bit further & change some controls but it has definitely worked for me, I've never been too adventurous with Audax & like to do the same rides all the time, I've done Bernard Mawson's series of events hundreds of times based on or around Doncaster.