Do you think I can do this fixed?

Fixedwheelnut 68" gear is a good allround long distance gear, 300km usually takes between 15 and 17 hours for me depending on how hilly it is.

Two brakes are good on long rides, I always use two as leg braking kills your knees :)
Good luck.

good stats... hows the scars?

remember seeing your holdsworth...nice ride!

Ray