I started off by first painting the cork roadbed with cheap flat gray latex paint so that any spots in the ballast later on wouldn't show up as brown. I don't really know if this helps because when I weather the track it will cover most the gray but it sounds good in theory.
I quickly learned that Gargraves track is nearly impossible to bend if it isn't brand new. Even the slightest amount of oxidation will cause the wooden ties to bind on the rails. You can spray it with WD40 to loosen it up, but that will later cause havoc if you paint the track during weathering. Forcing the track to bend and then securing it every few inches with screws works, but I didn't want unsightly screws (and the 2" of foam would have required me to use 2.5" long deck screws to reach into the wooden table top under the foam). Since I am mostly working on straight track right now I am relying on heavy weights to hold it in place until the caulk cures.
Then, some like-new sections of Gargraves track were tested in place. To minimize cuts and gaps which require a bit more effort than trimming HO scale track, I worked from the edges of each section to the middle. I clamped a piece of black Gatorfoam to the edge of the layout and laid the track to that with just a tiny gap (to allow for any future expansion of the rails). My bandsaw and Dremel tool made quick work of cutting the track where necessary.
Before I could glue the track down I had to also wire it up. While it is possible to solder electrical wires to the sides of the rails, one nifty trick is to use uninsulated male quick connect tabs and snap them into the underside of the Gargraves rails. I went with 14g wire for the feeders.
You also must drill holes in the cork for the wires to pass through before securing the track. It is a slightly fiddly process.
Gargraves track's wooden ties insulates the outside two return/ground rails from each other. This is advantageous for signals and accessories, but to ensure good electrical contact for the trains you want to power both rails. One way to do this is to solder jumpers between the two outer rails parallel with the ties. I was too lazy to dig out my soldering iron so instead I just dropped extra feeders. It also will avoid problems later on if I want to use one of the outer rails for triggering signals or accessories, as cutting the buried hidden feeders is near impossible.
Once I dry fitted everything to make sure it worked, I applied a layer of clear caulk and attached one piece of track down. I then heavily weighted it so it wouldn't budge. I ran out of weights pretty quick so I could only do one section of track at a time, but over the course of a weekend I laid the main line. It was a huge inefficiency in time, but I found it helpful because I wasn't used to working with Gargraves track before and I had to remember where to add feeders wires so the slow process was helpful. If I switches to long deck screws and washers I could use them between the ties and speed things up, and later pull the screws.
One benchwork joint required some light shimming with 0.030" styrene, that I caulked down and then flooded with superglue for extra security.
Three-rail switches have a lot of extra pieces of rail in the middle area, and their frogs are unpowered plastic. That means that when a locomotive is passing through a switch there are opportunities for it to stall out (especially the middle pick-up roller). Operating locomotives with middle pick-up rollers spread far apart avoids this. To address this potential problem, switches can be purchased from RCS with pre-wired jumpers to avoid stalling. Below is a pre-wired switch.
To be safe, I wanted the inner point rails also powered but many of the used switches I bought didn't have the jumpers, so I had to add them myself. Not having suitable solid core wire on hand, I used pieces of code 100 nickel silver HO scale rail. You can see two of them below, as well as an extra feeder wire I added as well.
After one weekend I had the 12' of mainline laid in place and I could start working on the passing siding. I couldn't believe how slow my progress was and how much more effort it took than HO track. I was learning new skills and also hamstringing myself by using caulk instead of screws to secure the track. But it was enjoyable too and Harrison had fun pushing a test boxcar along the track.
