Cyclocross racing with fixed gear road bike with cross tires I would like to take part in three local cyclocross races in the coming weeks but have a bike dilemma: 

Should I convert my track frame to a new fork and put one cantilever brake on it and change the tyres, or change the tyres on my Kona road bike (I checked to be sure that there is enough clearance for cross tyres) and race with road bike style calipers but increase the calipers clearance to the rims? At the moment putting cross tyres on my road bike is the cheapest but no one uses calipers so I assume it's a stupid idea. But is converting the track bike silly too? All races are flat, btw.
Neither option is a good idea:
If you use caliper brakes for the cross race, they can easily be filled with mud and became useless.

If you go with fixie you'll be very slow on steep uphills and it will be dangerous to downhill without a freewheel.

But you can try if it will be very simple race :)