Glad you have found my thread useful Rob 🙂
I can't overstress the value in planning everything very carefully, and spending a lot of time on getting the track-laying and wiring just right. A for three-links - to be honest I find them reasonably easy to manage on freight stock; using a magnetic link at the end of the coupling makes things far easier. I've found that they don't work so well for corridor coaches though, as I haven't been able to figure out a way of getting my coupler/uncoupler to them underneath the corridor connections. So I'm now using Hunt couplings for coaches, with a screw link only for coupling to the loco.
I also think it's a really good idea to make mock-up buildings too, gives a good feel of how things will look, and helps you to plan, and with clearances and sight lines and so forth. By the way, I know a chap who could make some finished buildings for you if you like! 😀