A traditional track plan but a "nice" implementation in 5x10 using Atlas-O track: The outside oval is O54 minimum diameter with O54 turnouts, and connections to a continuing mainline to the left and right. The inside route is a return-loop to return-loop plan, with O45 diameter and O54 turnouts. The route climbs to 6" in height crossing over the lower-level tracks, with a grade of about 3.5%. No 'S' curves on the mainlines. Using three lengths of flextrack, the rest is sectional. The ridge-lines crest at about 13" in elevation.
The 10' length is just enough to let a 10-12 car train stretch out a bit. The minimum center-rail distance is 5".
There are opportunities for attractive scenery and good views, with the ridge-lines, bridges, tunnels, and cuts through elevated terrain. The 5' width allows a comfortable reach into the layout from each of the long 10' sides. 5x10 is small enough to allow a table on castors to be built, which can roll into a corner and then pull out for viewing, construction, and maintenance.
Ballasted Atlas-O track can be very beautiful, but requires more work to ballast (compared to Lionel FasTrack). The turnout switch machines can be unattractive and unrealistic (FasTrack switch machines are integrated in the roadbed, and can be purchased with command control), so under-table machines might be used - more effort and work.
