- well, welcome to the most addictive, infuriating, frustrating and best hobby around, and one that will keep you perenially "BROKE"!
As I mentioned - you have a good start, the only thing I might suggest, and this is a sort of unwritten rule of thumb thing, try not to design your track plan around the edges of your benchwork - try to incorporate a little variation, a curve or two - even small ones, it just adds to the interest and gives you some options for scenery
I have built quite a few layouts and always focused on getting the track work down - once that is in place and working well I could then run a train - even if I only had 1 of them to run - I could achieve the purpose of the layout
My way of thinking is this - the track work is the most important because without it - nothing else happens or matters so to speak. Then I get an engine or two and half a dozen pieces of rolling stock or passenger cars, which ever you want to run. Then I sit back and think about the scenery and where I want things to go and how I want it all to look. It is a slow process, but a very rewarding one as well