I have sixteen years with compressors under the hood, never had one burn up. (Disclaimer, if you mount near the exhaust manifold or anything labeled "Hot" your results may vary.) The fuse box usually has a nice cool cubby near by.
I did buy a second compressor when I bought my 2012, left the 15 year old one on my 2006 because I couldn't part with the truck, previously it had been under the hood of a 93,97,00,02,05.
If you were to mount a compressor to my frame rails it would be full of water.
Most trucks have a rubber grommet passing through the firewall that will easily take a pressure guage line and control wire for manual.
After spending the extra for the remote with built in presets, I adjust my ride more frequently to match the load of the day.