JR, I bought mine on Ebay, and don't 100% recommend the seller.
(Had some problems with the way they shipped the stuff, and although they straightened it out....it took a couple of weeks.)
I think with shipping, I ended up paying $80, for 6, 5 foot pieces.
I did see somebody selling the stuff outright on the 'net for around that price.
I don't see the seller who I bought mine from on Ebay with any to sell right now.
This guy always has lots of 6 pieces, but is $10-20 higher.
http://cgi.ebay.com/ebaymotors/E-TRACK-6-5PCS-ENCLOSED-TRAILER-VAN-CARGO-TIEDOWN-GLV_W0QQcmdZViewItemQQcategoryZ50466QQitemZ4570869887QQrdZ1 Somebody is always selling some E-track on ebay, just do a search for 'e-track'.
6 pcs of 5 foot etrack weighs 57 pounds, so shipping eats you up.
If you need a LOT of it....make sure you check shipping costs.
I did a search on Google and found one seller 'claims' to have 5 foot painted sections for $8.99, but I couldn't find shipping costs.
The stuff is easy enough to cut with a hacksaw, or a jig saw.
I bought 2 pieces of 2 foot sections to fill in some gaps, and it ended up costing more than the 5 ft sections. Buy the big stuff, and cut it....
Anyway, back to the trailer.....
It took me quite a while to get the nerve up to cut a hole in a rear door to mount the air conditioner.
When I finally started cutting, it went fairly easy.
The door was constructed as I guessed......outer aluminum frame, with some wood bracing, and a center foam core.
I cut through the inner plywood, and foam layer first, leaving the outer skin intact....in case I screwed up!
I kept measuring...and double checking. Didn't want to miss anything.
When everything looked good, I mounted my wood framing for the a/c, and screwed it in.
Then....I cut the metal outer skin. I drilled a hole on each corner of the opening, and used a cheap metal nibbler I bought at Harbor Freight.
($6). This worked pretty well....and wasn't prone to get away from me like a power tool.
The foam is only lightly glued to the interior and exterior sheathing, so it was easy to get rid of it.
I need to fashion some sort of trap door or flap to cover the hole on the outside, since the a/c unit won't be permanently mounted there.
I don't think the door will handle the extra 50 pounds, particularily when opening and closing repeatedly.
I'll just open the trap door, and slide the unit in when I want to use it.....
Oh yeah, I did screw up something......
I forgot to take into account the handle on the rear door cam when I did my measuring.
When I had everything bolted in, the handle hit the a/c unit, and wouldn't close.
I initially thought about cutting off the offending 2 inches or so with a hacksaw....but ended up just bending the end of the handle outward a bit....
Anyway, I'm over my 'fear' of cutting holes in the trailer, and am hunting a few opening windows to put in.....
I've got some more stuff to do this week, before heading to Road Atlanta for the AMA races friday morning.
Oh yeah, JR, the inverter showed up, and it will power the A/c unit. I just hooked it up, and ran it for about 10 minutes.....not a serious test, but it barely got warm. (The inverter)