Are you mounting it on a wood surface (eg. train table)? or is it just temporary on the floor?
If using a train table, you could just drill and bring the switch up from the underside and it would easily fit between adjacent tracks.
On our 4x8 Christmas layout, we have 3 sidings with on-off capability. I just ran the buttons back to the control panel, near the transformer in one corner of the 4x8.
They are low enough profile that they wouldn't even reach the top of the rails if they were mounted alongside any of the tracks.