Hughes,
Is your difficulty finding the best line, or holding in once you have found it. I'll make some asumptions here. In hare scrambles, often once the lines and ruts are formed you actually want to ride next to them but not in them. Generally by then it is too rough to make time. Speed in hare scrambles comes alot from making your own smoother lines that thread in and out of the rough ones that already exist. For an example, given a long LH corner (say about 3rd gear worth) there will generally be a whooped out line, possibly a rut, that follows the arc of the corner. Following the normal line is slow and rough. A better plan for these is to "square" off the corner. That is to enter the corner to the inside left of the line, aimed at the apex of the corner, turn tightly at the apex then steer inside to exit to the left of the line again. This way you spend most of your time on smoother ground. A couple of tips:
1. always concentrate and look exactly at the line you want to ride. Your bike will always steer where you look (even if it is at a big rock).
2. KX loves to be steered by weighting the pegs. Try railing those corners standing using all your weight on the inside peg. Play with peg weighting a bit, you will be surprised.
3. People will ride the rough line all day when a smooth line is 12" away. Use your smarts and always look for the smooth line, generally the sides. Faster with less energy. The KX steers well at speed. Use its abliity to thread in and around the rough stuff.
4. If you get a chance, walk the course. It is much easier to get an idea of where the smooth lines are. In my MX days I would walk up to 10 laps, studying each corner to find the best apex, lines in and out etc. Good luck. Cam.