I was semi-idly thinking that offroad scooters or skates might be a viable if unusual way to get down the slick, ball bearing like fireroads that we often have here particularly on Mt. Diablo and Rose Peak.
I did a quick Google and found that I wasn't the only one thinking along these lines. There are a lot of off beat solutions. While Rollerblade has a discontinued off road skate called the Coyote:
the most interesting looking skate is called Trailskate by Gateskate:
In the scooter realm, there are lots of bike x scooter possibilities listed at:
The coolest one being from Germany and called the Mountain-Scootboard ant only 500 Euros (!):
A really interesting one that really isn't for my purposes, but still fascinating is the Trikke:
and there's also the more bike-like Diggler:
What's interesting to me is that the more skate-like contraptions are still under the radar as far as off road laws go. Can skates be used on a no bikes trail? Fortunately, it's not really an issue as the problem I have is with gravelly fireroads and they usually allow mountain bikes (backside of Diablo, Montara Peak, Mt. Tam) and I intend to be biking most of them. The exception is Rose Peak that only allows bikes at the beginning of the trail and then it's hikers only. In that case, I would carry the skates with me and then use it going on that steep downhill which allows bikes. Or one could just lock the bike to a tree out of the way as someone who climbs up that far is not looking to steal a bike or whatever - I probably should just try that first since I already have the bike.