Hi there! My name is Jeff, I build trails and teach biking lessons at MCBP. Here's the skinny:
XC - there is an awesome loop divided by color into 5 sections (though not by difficulty). The loop can be accessed by several points within a quarter mile from the top of the lift, and all trails are marked quite clearly now (after a few people found themselves to far off lands). Most of the ride will be smoothe but sometimes technical single track with a decent amount of climbing, but some long flowy downhills as a payoff. Some off it runs on old access trails - but the mossy, green, fun type - not the loose, gravely fire road type.
Downhill - If you've only ever ridden a beach cruiser, the lower end of the beginner trail might make you peepee. However, with any bit of minor experience in trail riding, the beginner trails shouldn't be too shocking to you. The best thing you could possibly do would be to reserve a lesson, which comes with a brand new Specialized Demo, lift ticket, full protective gear, and a lesson with yours truly. Then we can discuss and practice in depth proper body position, pedal position, foot position, breaking, cornering, bike and body separation, etc. But if you do so choose to take your life into your own hands, then your best bet would be to ride Greenhorn -> Domboo for your first run. Then either breakout or ego trip, then work your way down to crap chute and Indy cross. Then go get a beer. I don't check on here much but hopefully I'll see you on the mountain!