I wanted to be a park ranger for a long time. A couple years ago I researched the aspects of it. Looked pretty dismal. Low pay, crappy people including other employees, low funds, etc... You will get to travel to different locations which can be a plus. I also found that a noob in the field really needs to pay their dues to get anywhere. Also if you are a veteran you are placed above most that apply.
If you want to pay you dues first, and test the waters than look into the Seasonal LE Program
approved by the National Prk service. You attend an academy put on through several colleges in the US, at your dime of course. After you graduate you can get a job as a Seasonal Ranger with Park Service, or possibly a full time state or local job.