My truck will do 100+ mph but I've never taken it that fast. Just ride sensibly. Also check out the laws where you are. You may be limited on how fast you are allowed to go. Brake wise the more the better. I have a coaster brake beach cruiser but I've added a set of hand brakes just to be sure. A bike that won't go is annoying, a bike that won't stop is dangerous!
Edit: Stay off the sidewalks! You are going too fast for the rest of the traffic there!
If it can't be broken I'll find a way!
I'm not lost, I'm exploring!