I am going to be installing this same pillar, I did one on my 99 ram a few years back and think i was able to poke through something in the firewall guess i will find out soon enough

 

Would I have any better access if I popped the dash bezel off, and maybe the headlight switch?

 

There is a rubber boot where all the wire looms go into the cab, by the steering wheel. Cut here & run your stuff. Seal with duct tape.
You can run a wire hanger up through to the A pillar from the fuse box, or vice versa.
These projects always take a lot longer than expected, at least for me.
I really love the gauges, they really tell what is happenning with the engine.
I found when I put them in, my LP was dead(no codes though). When I put in my Campaigh pump, it only lasted 10k, so it saved me there.
In the process of switching to an Airtex pump. It is a time thing, not enough.

 

I got most of it done yesterday. I found that removing the kick panel right below the dash was really simple (3 screws, then pull the panel to disengage 2 clips) and gave me decent access to the area under the A-pillar and behind the fuse box. I used double stick tape to fasten the EGT amplifer box there too. I was able to snake a piece of aluminum ground wire I had (coat hanger would've worked) between the A-pillar opening and under dash area. It went right past the fuse box, so as I pulled my harness down, i was able to grab the breakouts for dash lighting (tapped on #5 fuse) and EGT amp (#16 fuse).

Then I drilled a big hole in the firewall, just to the right of the some ABS-looking electronic box, just above and to the left of a steering column bolt. I got the EGT and boost gauge hooked up, then ran out of time. I already have my IP bolt tapped, got the needle valve plugged now, just need to connect the nylon tube for fuel pressure gauge at the IP, then tidy up the wire routing, silicone the firewall hole (OK, maybe duct tape ) it should be good.

My tweeter is not workingt though, I think it was before i tore it all apart. I hope I reconnected the factory connector, but in hindsight I'm not sure, it was such a mess of wires and tubes. It will be a few months till I forget how heinous it was, til i think about pulling the A-pillar off to check. Maybe i can pull it down a little and peek in with a mirror.

Its nice with gauges, 24psi and 900deg F, thats what I've hit so far. I'll monitor them for a while to get a good baseline before I change anything

 

I had mine installed on top of my previous piller. I had to grind on the tweater hole on the privious piller. It was a long process but it all wored out. I had the fuel prs on the bottom. Because my friend who installed it for me said that you dont want fuel pressure running all the way to the top incase of a leak. But it doesnt really matter its up to you.
Hope it all worked out. heres a pic of mine.