These are variants of your four criteria, and perhaps far too specific:
* distance range: 1-2 miles, 2-5, 5-10, 10-20, over 20 (with corresponding km numbers)
* vertical ascent: flat, 100-500 feet, 500-1000, 1000-2500, 2500-5000, death march
* water hazards: guaranteed dry, easy stream...