As far as what to expect during a cross race...
The courses typically aren't what I'd consider technical. At least not compared to some of the mountain biking I've done. The "worst" I encounter around here are some off-camber turns. Whether or not a course is "fast" is entirely dependent on you. With that said, some courses are faster than others. Some have more running, some have more pavement.
What to expect? Pain. 100% from the gun.