You could have a look at the 3 part article I wrote in the "ME" Nos 4289,4291 and 4293 describing how I did it. You may find that helpful. I have found the system I used to create the track bed has worked well for me. I used PNP track components and have found them a very good system also (satisfied customer, usual disclaimer)
If you are building points, Doug Hewson's EIM article is very useful, but don't use brass screws to fasten check rails and frogs made in aluminium rail. Mild Steel is less likely to result in electrolytic corrosion than is brass and should be preferred. For points sleepers I used afrormosia
Regards, Tony