Some states allow references from supervisors without PEs who can show they have equivalent training and experience to PEs. It's a judgement call whether to accept those as equivalent. Also, NC has some specific language about military experience (this is in a different thread on this board) that indicates they are skeptical of engineering experience gained in the military unless there's a direct one-to-one correlation to what civilian PEs do. My deepest, most rigorous engineering work was as a commissioned officer in a submarine shipyard.
Much of my experience since the Navy has been in fiber optics which doesn't map easily into any of the license areas (EE, CE, etc.). It's a little bit of about 4 examination test areas + a lot that's not covered on any exam but is in fact engineering. There's no fiber optic engineering exam.
Some old employers are out of business. Some old supervisors are unavailable for references -- as in, they're dead. I have to self-verify some of my old jobs.
This means that my application won't be a black and white, 15-second decision ("4 years as a DOT engineer working for a PE? You're in").
So someone at the state will have to do some thinking to decide if I make the cut. I reckon a high board score (if they saw it) might help ("sharp guy"), but it sounds like boards don't see scores except in Texas.
My undergraduate department when I was in school was perversely named "Aerospace and Mechanical Sciences", not "Mechanical and Aerospace Engineering" (its current name). My transcript shows the old name. The transcript also printed out course titles with cryptic, unhelpful names - " Par df eq", "Mec Sds", "Fl mec". Even though my transcript explicitly said I earned a "Bachelor of Science in Engineering", when I applied for a nuclear engineering graduate program a few years back, the departmental chair turned me down saying I had no degree in mechanical or nuclear engineering.
That chairman also said I had no background in nuclear even though I explicitly spelled out my Navy work. He was not an American citizen and had no knowledge of the Navy's nuclear program. When I mentioned there was a submarine base with 8 reactors in our own state, he was surprised to hear it. (As it turns out, the U.S. Navy has a contract with a competing nuclear engineering program in another state -- they fly in professors to offer graduate courses on that base).
So I'm wary of bureaucratic obstacles.
Finally I'm mindful that there's a bit of a catch-22: much of my technical experience was as a self-employed consultant on fiber projects. If that is acceptable as experience for the PE, does that also mean I was therefore practicing engineering without a license?
I never held myself out as an "engineer" or said I was performing "engineering work" however I'm not keen to go to a lot of trouble only to find I end up with a fine instead of a license.
Lots of gray areas.
Get that license while you're young!