Some n00b Questions: tie downs, shocks, swaybars, etc.

I had dually Firestone valve/gauges mounted on the floor of my truck beside the seat with inflation valve on it.
So I could inflate bags separately, could see the pressure each time I open the door and inflate the bags with shop compressor at home, or portable 12V compressor in emergency.
Those $15 12V compressors do have short life what makes them pumping less and less pressure, but if you use them for emergency only, they will do the job.