I ride my Surly Cross Check on trails just like that and little dirt and gravel roads. She likes 'em! 
http://surlybikes.com/bikes/cross_check_complete/ Anything more exciting than stroll-able trails, I wouldn't ride any bike on. Cuz I'm just not that coordinated...
If I did things like that more, I'd keep knobby tires on; but mostly I ride on asphalt so I use smooth tires.
Last edited by KnottedYet; 02-02-2010 at 02:29 PM.
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson