Hi Glenn,
I'd suggest you scout out the location carefully in advance, to get a better idea what equipment you will need. Check for a couple locations where you will be able to set up to view the action, without any obstructions and subject to any limitations of the event organizers and course.
Then try to get two cameras set up: one with a longer lens aimed at a more distant corner, for example, and the other with a shorter tele to capture the goings on at a closer corner. Zooms may be desirable, particularly if you will not be able to move about very freely. However, primes could possibly be faster and sharper.
Get the fastest lenses you can afford. That will give you access to high shutter speeds to stop action, and to shallow depth of field to isolate your subjects against a nicely blurred background.
Get the lenses a day or two in advance, so you can practice a bit to get nice and comfortable with them, before the real action begins.
If possible, use tripods and pan shots. A monopod will also work in some circumstances. Big lenses on small cameras can feel very unbalanced to try to handhold.
Some other suggestions:
Don't try to get every shot. Watch the action for a while first, to pick where and what to aim at. Re-evaluate every so often, too.
Try both higher frame rates (neither camera you are using has very fast frame rates) and time single snaps for the peak of the action.
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