Channluv, last year I was passed by an in-line skater going UP Oak Hill in Harvard, MA. He passed my DH, too, who was going faster than me. I heard the guy, but my brain couldn't assimilate the image, as he was also wearing a bike helmet. This is a hill that is used for training by racers, so it's not some wimpy hill! And, he was my age, not some young guy.
All of these stories reinforce why I don't ride on paths, although, we don't have many around here. We want to go on one that starts about 7 miles from my house, to go out for breakfast, but it's either going to have to be really early in the morning, like 6 AM, or after 9, to avoid the commute traffic.