Put the radio in the glove compartment. It's out of sight and out of the weather.
Larsen makes a nice stainless steel (painted plack) "L" bracket for NMO mounts. You could install it in the groove between your hood and front fender. Or, on your rollbar if you have one.
Larsen part No. NMO TMB 3/4 B (drop the "B" from the part number if you want the chrome version)
They cost $6 from www.hamantennas.com
I use one of these mounts on my car. Works great and when you want to sell the car, you only have 3 small screw holes to fill.
If you need the mount & cable assembly, Hamantennas has them too.