pull the distributor cap. if you have points, you should have a ballast resistor or ballast wire. if you have electronic distributor from volvo, then no ballast resistor/wire.
if aftermarket pertronix, it will need a ballast resistor.
crank for 10 seconds, let it rest for 60.
repeat (this will get the fuel pump to pull fuel and get the oil flowing in the motor
then pump the throttle and start normally.
I would mount it under the light myself. second location would be sideways on the side bunk bracket.
ask for a motorcycle trailer tag. they are much much smaller in size.