Not sure about the dynamics in the Denver Metro area but you could give residential/commercial irrigation a go if you enjoy being outdoors.

Starting pay is probably $20/hr down there (with no experience). You'd have to put in a few years with a company to learn the trade, but after there are pretty low barriers to entry for branching out on your own. $100+/hr is very attainable (labor + parts markup). Three to four months off every winter that you can use to work another job or use the time as you see fit -- ski, travel or whatever.

Also, maybe look into having a professional redo your resume. There might be a problem with it that you're not seeing, hence no interviews. You can pay someone from a lower COL country, like India, under $100 to completely craft a professional ATS compliant CV, cover letter and resume.