my wiring already existed - id come thru the top right corner or top right side and seal it.
as for the lighting / number of strips per bay...you can see the diff in my pictures...
the cooler bay has one strip over the open side of the bay (not over the cooler since that would be a waste).
even ONE strip is a lot of light - especially if its dark.
if you look in the REAR bay (tools hoses & boards for my leveling jacks)...that bay has
TWO strips soldered together (150 leds)...the light is more uniform and consistent across the bay...i did this because of the half shelf and the need to SEE if im after tools etc.
the FRONT bay (out door mat & chairs) has a FULL (depth) shelf and so i put one strip of 75 LEDs in the center top and then one strip under the full shelf.
my factory lighting used the metal box/bay as ground, so you only really need to run one 12v (fused) wire
I would run the strips across the front along the length of the bay...its gets the lighting IN the bay and theres NO GLARE (which i believe would be the case if you ran the lights along the depth)....mine are stuck to the back side of the STIFFENING lip of the box.
I dont recall the dimensions of my bays...i know theyre 24 deep...and theyre more than 60 wide across the front (the cooler is about 30 inches wide).
IIRC the automotive bulbs were 2 or 4 watts (and they SUCKED)...they get hot and they provide zero light (in comparison to the wide coverage of the LED strips)....those automotive bulbs pulled 8 to 16 TIMES more current (iirc i measured 1/4 of an amp at 12v)...but im reading reviews that say they pulled 350ma per strip....i dont thing you have to worry about them killing your batteries (for a few days).
im reading reviews that claim each strip of light is on par w/ a 13w fluorescent tube...im not sure i agree but they are bright.
to me the master switch could be a good idea BUT...opening a bin, hitting the switch and having NO LIGHT (because i forgot to turn the master on) would piss me off, i know it !