If I remember right, my 92 had a grommet on the passenger side that I ran through. Power on Pass. side, remote and RCA's on driver side. I'm grounded to a bolt under the trim panel on the bottom of the cargo area, right in front of the tailgate. Doesn't look good, but is functional. Just got a streetwires ground terminal so I'ma move it before long.

 

It may be the easy way but its also the stupidest. Having your power wire ran through the door can cause it to pinch, or slice open. If it slices open say good bye to your amp.