Wiring Garden Railroads

I am in the early planning stages of my garden railroad and am wondering how to wire the system. In my youth, I modelled Märlkin and one hook up to the catenary and one to the ground and I was set. Now I am dealing with much greater distances. What references are there for dealing with this? The same goes for signals, switches, et al. Thanks

I ran a pvc pipe underground a long the side of my tracks, when ever I needed wireing to come out I would make a hole and pull the wire thru, then pach the hole as best I could to prevent water from finding its way in, of cores I do think it would have been easier to have just run radio controll.