Chris do you have a second battery? Or are you planning on getting one? Best install option, IMO, is to wire it directly to the second battery- that way it can be "always on," but when you start the truck again it won't power spike the radio- I have wired radios about every possible configuration and in my opinion this is the best way.. if you don't have the 2nd battery yet then save some wire so you can move the wires when you do.
Having the radio switched on with accessory is a bad idea, because you shouldn't need a key to monitor or transmit, and you don't need the power spike at startup. Having it wired to the starting battery direct is a bad idea, again too many power spikes can potentially let the smoke out (I'm sure there's a more valid reason than that referencing electrical fundamentals). Best option is wire it directly to the second battery.. which doubles as a nice backup voltage meter for battery 2.