I went out on a ride today and along a fairly straight and empty road devoid of cars, I rode for about 100' several times with my eyes closed. It's not hard. Stupid and dangerous perhaps, but certainly not difficult.
I decided to ride at a faster speed rather than slower because I wanted the centrifugal forces to help keep me upright incase I hit something (bump/hole). I was going about 15-18mph.
I found that I pretty much stayed in the center of the road and didn't veer one way or another. After getting somewhat comfortable (if it could be really called that), I started weaving left and right gently. My hope was again to stay in the center of the road. I instead wound up on the right side, perhaps because I'm right handed.
The most challenging part was the wind. A storm came through yesterday and it was very gusty today.