hats off if you do it. i've done it twice in under 90 minutes and both times were tough going. what i don't like about it is that i find it boring. that last climb just before the end is a doosy. what i like about the alpe are the numerous switch backs. i know, same thing over and over but it does break things up a bit.
90 minutes of indoor riding while it is so nice outside...maybe in 6 months.