...a hot trail would be referring to a path that was recently traveled, and so the ground is (either metaphorically or literally) still warm with their presence. If you were tracking someone and they had recently slept somewhere, made a fire, etc. the area would still show signs of their *recent* activity, and so the "trail" would be "hot."
Hot on the Trail - 2010 Elderberry was released on: USA: 21 May 2010
Hot on the Trail - 2010 Perslane was released on: USA: 10 March 2011
Hot on the Trail - 2010 Coconut was released on: USA: 3 March 2011
Hot on the Trail - 2010 Mustard - 1.8 was released on: USA: 2010
Hot on the Trail - 2010 Lamb's Quarters was released on: USA: 27 January 2010
Hot on the Trail - 2010 Mustard 1-8 was released on: USA: 2010
Jerry's Red Hot Trail - 1917 was released on: USA: 21 June 1917
Hot on the Trail - 2010 Wood Nettle - 1.4 was released on: USA: 2010
Hot on the Trail - 2010 Cattails 1-7 was released on: USA: 2010
Hot on the Trail - 2010 Dandelion 1-5 was released on: USA: 2010
Hot on the Trail - 2010 Rosehips 1-15 was released on: USA: 2010
The cast of Red Hot Trail - 1920 includes: Fred Kohler Magda Lane