Elevation figures tend to be the least accurate information we get about ride routes. GPS is notoriously poor at at determining elevation and while barometric methods are excellent during periods of steady barometric pressure they can go out the window when pressure is changing rapidly. He is saying it will be his last year but Rich “Mr Geobike” Ketcham is doing the pre-ride again this year. He generates his own data using a custom system that he put together. I have no idea what his system does or how but I will go out on a limb and say that I trust his data more than any other commonly available source. I do not, however, know if the daily reports we get from the pre-ride are based on his measurements or the barometric readings from someone’s Garmin. In a week or three the Geobike data online should have been updated with his latest measurements so I would check them around the start of July for the best available data.