I was looking at the mods that Fred In B. C. was doing and will offer my 2cts worth on the drawer he needs. Maybe you should add wheels to the drawer bottom so it can just roll on the floor you added. much easier than guides and tracks. Just needs a latch to keep it closed until you need access. You have done very nice work so far. I'm sure you will create a drawer that will work well in your project. Only trying to be helpful. Good luck & happy trails to you !!
Duane