Just a thought, just a suggestion, since your space is relatively Limited, and I understand that you want a continuous run most people do, you may want to consider having a switching kind of layout. That in lieu of just going around in a circle. In that small of an area, it's not going to take long for a train just to loop around the track. That is a lot of expense to build a layout and then all it's going to do is circle around. You could do that on the floor and save a lot of money.
In my estimation, the biggest mistake that most people make over the many years I've been in the hobby is they give themselves nothing to do once the layout is complete. You need to have some kind of interaction with the trains to have enjoyment with it's going to sustain your interest. There is a great deal of potential building in some Industries and some sidings and getting some kind of a system going to where you can deliver and pick up cars from various points. You know, kind of like a board game. Operations is a huge facet of this hobby that the majority of people miss. That is why so many people lose interest or continuously are rearranging their track thinking that's the problem.
The other thing that occurred to me is you might want to pick and focus on a theme. Focus on that theme and really really detail the layout. Layouts can be done so super well in a space like this by really focusing on a particular theme and detailing it with the things that are around in real life.
If you're really just dead set on circling, I would suggest this to you, why not build two completely separate levels with one a continuous loop where if you just want to sit back and watch it Circle you can and on the other build an actual model of a railroad that will have a purpose and some operation? That would give you the best of both worlds.
Good luck to you with your project and congratulations on your new space. I would really think long and hard about exactly what it is you want to do and what you want to accomplish and what it is you're going to do with it once all that is done to keep yourself going. My two cents now going on about a thousand bucks.
