Right now, I'm faced with the choice of what to do with the brakes. I could leave the rear brake on and just take off the front brake, or, I could take both off, and put it on the two front forks. I'm fairly conflicted right now, and for my own benefit, I'm listing out the pros and cons for both.
For putting it on the front wheels, there's the slight advantage of forward momentum, plus, it might be more road legal, having two brakes instead of one. It could also cornering easier, being able to lock one wheel and pivot. Last, I think that it would be pretty cool to have a left brake lever go to the left wheel, and a right brake lever go to the right wheel.
But, the rear brake should work fine, considering that this is not a speed machine. And, cartbikes have a tendency to tip over if they corner to hard, so cornering any harder than I can to begin with is probably not any better. It'll be a little bit less work. And it would reduce the risk of flipping forward. Though the wheelbase should be long enough to make that impossible, it would probably be better to keep as much torque off of the front connections as possible, seeing as they are the weakest spot in this whole project. And for that reason mainly, I'm going to go with a single rear brake, at least for now.