Ive heard it described thus...Instead of technical bits linked by fireroad as most trail centres are ,the Marin trail is fireroad linked by technical bits....ridden it and tend to agree with this.Sorry.
You're probably right on this one, but that's partly why I love it - it's a little different, and why does everything have to be technical all of the time anyway?
As a teenager I spent a lot of time riding round the Gwydir Forest on a fully rigid MTB a couple of years before the Marin Trail was even in existence. Back then it was almost all fireroad with the odd cheeky footpath here and there.
But it was still a great ride even then, more about the joy of being out on the bike, thinking about navigation, in a great location with great views than pure technical skill.
Hell sometimes I go out on my MTB for a mostly country lane based ride, linked with a couple of muddy sections and I still love it.
I guess at the end of the day, if you've been brought up on a diet of newer more Gnarr trail centres with cafes, bike shops and perfectly manicured trails then you probably won't get the Marin Trail.
I'm getting to the stage however when I tend to ride natural stuff more of the time. Trail centres are fine occasionally but these days I find them all a bit 'samey'. I much prefer the challenge of exploring natural terrain with an OS map. Finding a new 'off piste' line down a mountain, or some cheeky singletrack that no one else has ridden. Usually involves a bit of 'hike a bike' or road/fireroad climbing/descending though - Heaven forbid