Range is nearly only affected by the size of your battery. All you can do is affect torque or speed with your gearing. (to keep it simple - there are more factors involved like a balanced setup itself, but let´s not think about that for now)
Vesc is capable of limiting top speed - ERPM setting.
If you need risers depends on what deck you´ll be using, which wheels, if you want a smoother, dampened ride and so on.
Build the rest of your board and then decide how much you need to rise this thing from the street