Most any current helmet will have more ventilation than the Bell Image MTB-centric lid I used to do this ride the 1st time in 1992
-- There are lots of stops for water, oranges and bananas along the way, --- but if you stop at every one of them the ride will take 6 or 7 hours
Nowadays, the oly real advantage a high -endy lid has over a cheapy is ventilation . Look at some of the popular tour de france helmets from 4 or 5 years ago --- enough time has passed that they have trickled down in price -- or just spend $200 or so for a new Giro or POC