How do I start from a specific line in the gcode?

Have you tried simply deleting all the gcode lines you don't want to run up to the point you want to start at?

Totally jinxed myself there.  I had the communication error again and it stopped at layer 512 of 598.  My print completely cooled before I discovered it and in hindsight I should have warmed the top of the print with my heat gun before I started printing again.
     I put x and y back in their home positions then I scrolled through the gcode in the editor until I found the last line it said it completed in the log.  Working back towards the beginning, I found g1 command with a z location and went back even further until I located the next smallest z location and put my cursor at the start of that line.  I scrolled back to the beginning of the code, held down the shift key and clicked on the first line after the m82 command the clicked the cut button in the editor.  After I clicked run it homed out and completed the print.
     As you can see from the pic it didn't want to stick very well because the model had cooled too much before the next layer.
     Thanks MrWetsnow for pointing me in the right direction.