I found Mattzo Brick’s website, and realised the huge number of options if I get into 3rd party tracks, specifically from Trixbrix. I like that they’ve added all the custom tracks to Bluebrick but now I have no idea what to make. I did start collecting images from online of various layouts for inspiration. What I should probably do is figure out the tables and layout arrangement and then see what I can fit on it. I like that the Trixbrix makes it seem possible to fit more on a narrower table, so should be able to get in two loops, plus stations or sidings. Trixbrix also sell bridges, whicch are probably cheaper than building a technic bridge myself - although not as Lego-satisfying.
Also found that Mattzo Brick;s website includes custom controllers, firmware, software and signals and all sorts. Basically, like a real model train set has. This is a lot, but I’m glad it exists. I suspect once I build a layout, I’ll get a bit bored of it - as it’s never going to be a full room size with so many routes. However, with signals and control systems, then you can do more with it. Part of me is hesitant though - it’s not “real Lego” but real lego doesn’t offer a great deal - colour detection, for moving/stopping/reversing trains when they see a certain coloured block (which is quite neat, and could be useful for a back and forth train), and maybe motorising switch points, so you can build a control console but I don’t think there’s much else that can be done with stock stuff.