I'll say I've been enjoying the 4Runner these past few months that I havent been doing much of any updating on this thread. I think they way I am currently set up works perfect for me.
First here's some pictures of my compressor install. I opted to install the compressor under the driver seat since it had plenty of space and allowed me to run the harness very easy without any issues. Also my 4Runner has ABS so the location where I originally planned to install it was already being taken up by the ABS manifold. When the time comes to install an ARB front locker I will probably relocate the compressor to the engine bay.
First I ran the harness to where it needed to be and then I mocked up the compressor how it would be positioned underneat the seat to make sure it would clear the rails as I slid the seat forward or backwards and the door when it is closed.
Because the compressor can get pretty hot during extended use I didnt want it to be in direct contact with the carpet and risk it getting charred or even worse catch on fire so I made a homemade heat shield. I cut out the 4 holes for the bracket and an additional notch to bolt the relay to as well. Then I painted it with some rustoleum satin.
Test fitment
Final placement
All Done. I mounted the switch where a factory blocking plate was, just popped it out and put the ARB in place, perfect!