Reddit reviews Nature Noir: A Park Ranger's Patrol in the Sierra

Honestly, not having any academic background in environmental science or forestry may be a hindrance to you. It's not always essential for a ranger position, but a lot of ranger positions are very competitive and you're going to be up against people who do have that that kind of academic experience. I would at least consider returning to school to get an AS in forest technology or environmental science. If you're willing to finish any 100-level pre-reqs online or through night courses at a community college, you can probably get an AS in a single year of full-time schooling. Look for a school that specializes in hands-on experience in particular.

If you're willing to do interpretive-type ranger work (history in particular), and also willing to work in an urban environment, then it is probably easier to get into the field of working as a ranger without any background in environmental science or a related discipline.

I would also not limit yourself to ranger positions. There are a lot of other types of jobs that could potentially fulfill your desires. Forester, wildlife technician, outdoor guide, etc, are all jobs that match your description.

Keep in mind too that seasonal employment may sound romantic, but it's not easy. Sure, the off season might seem like time to pursue your personal interests, but the reality of it is often applying for jobs, applying for unemployment, eating ramen noodles, etc. Any plans for starting a family that you may have are going to have to be put on hold until you can land a permanent position, and that may not happen for a while. You say that you have no desire to have a family any time soon- but that can easily change in a short period of time (I've seen it happen to close friends).

Another important thing to remember is that most permanent ranger positions are law enforcement positions. This often means less time spent hiking and enjoying the outdoors, and more time spent driving around and dealing with drunk, obnoxious people. Some National Parks even have a jail onsite for dealing with people caught committing more serious offenses. These positions also require completion of a law enforcement academy to be eligible even to apply to. (If you want to read a good book about what it is like to work as a law enforcement ranger, I recommend Nature Noir, by Jordan Fisher Smith.)

A good way to get your foot in the door would be to apply for a seasonal position with the Student Conservation Association. Some SCA jobs involve a fair amount of ranger-like work (backcountry patrol, public interaction, etc.). It's also a good way to begin making contacts and building references. The pay for SCA positions is minimal, but you do get a sizeable chunk of change at the end of your internship to put towards your student loans. While many SCA interns are folks still in college or recently graduated from it, it's not unheard of for an older person to use the SCA as a way to segue into an environmental field.

As an older person getting into the field, I would say that potentially your best asset is your maturity. Most rangering work is fairly independent in nature, and applicants with a proven ability to work efficiently and safely with minimal oversight are always going to look attractive to those doing the hiring. So be sure to emphasize any experience you have that displays this in your resume/cover letter for any job applications.

I hope this helps! :-)

I've know a number of forest rangers and I read a pretty good memoir of a ranger that worked in the American river valley that had to deal with a wild-west style squatter town that sprung up due to a jurisdictional loophole. I can't remember the name of the book, I'm on mobile now, but I'll look for it when I get home. While you may have been backpacking for a long time, it doesn't mean your experience is indicative of reality.

edit: Here's the book if anyone is interested