Here's my layout in a 9' x 12' space. I'm using Fastrack, but that should translate OK to Ross/tubular. There are two mains, a long passing siding, and a small yard. The inner line has reversing loops built into its design and as long as the train on the inner loop is about 13' or less, it can stop in the right place and allow a train on the outer line to come through and reverse direction. Inner loop min radius is 048 and outer loop min radius is 060. I have a Fastrack Extended Truss Bridge on the outer line crossing over the walk-in area.
Note the way I'm using 072 switches for my crossovers w/o creating an s-curve. Maybe something like that is an option for your plan as well.
Please ignore all the garage junk 
