Hi Jeff. My first O gauge layout was a 5 x 9. It was O36 atlas track, five 036 switches, reversing loop but it did not have elevated track. But an elevated track loop independant of the lower track could be done. I will draw it out for your consideration. I really liked that layout and it provided many enjoyable hours of switching.
Edit: Fwiw attached is a crude sketch from memory, 1990s! I liked the look of the siding coming off the main loop as drawn. I ran an MTH PRR consolidation with a box car, gondola, and cabin car. Hope you enjoy your project.
