There's a lot of steep hills in this area, and the roads are smooth. There's a lot of traffic for about half of the 16 miles, but the second half is through neighborhoods and back roads. On a FS XC 26lb mountain bike with slicks my fastest was 1:15. Typically, I get there in 1:05 on a 30lb 25 year old touring bike. Once, when I was in a hurry I made it home in :45 on the road bike. The only time I rode the route on my modern lightweight road bike, I was mapping it out, so I have no idea what difference it would make.

I'm a big believer in road bikes for the road, mountain bikes for the trail. I mean, it kinda makes sense if you think about it.

Az