So I have a prefab bridge over some water.

When you guys make a road, do you normally use another brush with the road texture or is there another way to do, also how would I make a ramp from the road to the bridge?

I'm not quite sure what you mean but I'll have a go:

To make a straight road just use a simple brush.

To make a road with a bend in it turn it into a terrain patch, and then make it how you want. I suggest following this tutorial ( Be careful, it is a Call of Duty 1 tutorial and the models and textures are not the same):
Curved Roads

To make a ramp form the road to the bridge you should just make a simple brush, switch to a side view of it and rotate it to the desired angle.

I hope it helps.