I take it no private sector civil/structural engineers care to give their thoughts? Maybe civil/structurals are not that prevalent in this forum.
I can chime in from the exact opposite position as the other poster, I am a civil who works on large scale pubic works projects. Education is a BSCE and an MBA, i've worked for consultants my entire full-time career, but did intern for a large DOT in college. I'm an engineering manager for a mid-size regional company and a junior partner in the firm. I didn't read the entire thread (quite lengthy!) so forgive me if I missed somethings that were said, but I think I get your general areas of concern and can shed some light from my perspective.
WORK DEMANDS: I would say it is true that I have worked 'more' than my government counterparts through my career, but I can say that it really depends WHO you work for. I have colleagues at a wide range of other companies as well as many clients/friends at DOTs so I can kind of gauge where mine falls in the spectrum. I work for a mid-size regional that places an emphasis on trying to provide a decent work life balance for people and pays OT/Comp time. Yes there are some periods where I am working/traveling quite a bit, but there are lulls as well where I take off early, take some long weekends, take a long lunch to have with my kids, or extend a business trip a day or two for pleasure, or am able to take my wife with me. I found I had a reasonable amount of this flexibility even earlier in my career, but have quite a bit of it now. Overall it's not terrible by any means. My friends who work at 'mega-corps' seem much less enthused about how things are handled. The larger the company, the more 'government like' it seems to be run in terms of bureaucracy, and the less autonomy you can expect. Overall I'd say the satisfaction level of the people I work with is on average about the same as the satisfaction level of the DOT workers I know.
EARLY CAREER SALARY: I think early in one's carer there is not a ton of difference in compensation, though for all our entry level engineers that are hourly they can rack up a good deal of time and a half (not sure if you get the same, some DOT's here are either budget strapped and can't pay over time or have more than enough people that nobody needs to). Enough OT that guys (including me) who have put their nose to the grindstone for a few years have funded the down payments for their first house out of it. But more than money, this more provides what i feel is the real benefit of doing consulting early in one's career: setting yourself with the knowledge and experience to move up in consulting LATER in one's career by having mentors through which you can learn the intangibles that you may not be exposed to in government, the business and marketing side, which is more what engineering managers and execs spend a lot of their time on. I will say it's rare for us to hire a DOT engineer into a senior management position because of those skills. The most 'likely' way to get hired into a consultant at a high level after spending a career at the DOT is to have CONNECTIONS there that make the likelihood of that translating into work enough to overcome a lack of knowledge in other areas, so if you will stay at the DOT but want to leave the possibility of consulting open, focus on building strong internal relationships with the key decision makers.
LATER CAREER SALARY: Good job doing your research on glass door, and I will admit every market is likely different in the pay so this may not universally apply, but at least in mine
good senior engineers can make a pretty solid premium, because in consulting you may have had the opportunity to stack many years of better than 'average' raises on top of each other that more reflect your true value and contribution, and are not stuck in a more rigid longevity 'step/grade' type system like many governments use for 'fairness' (you may be able to tell i have always hated this concept). In short, while a glass door average might not be a ton above what DOT engineers might make, the range is almost certainly much wider. In the basic sense, when we do business planning we essentially set salaries by what we can negotiate for billing rates and what kind of multipliers we need to achieve. This doesn't mean everyone gets paid the same, or even close to the same. All we need to make sure of is that the position on the whole for a certain classification is hitting the right average, but we can be as far above that (or below) as the individuals contributions would dictate. If we can allocate say 4% raises this year across the whole payroll, Superstar Steve might get 6.5% because he kills it and Dudly Dave might get a 1.5% cola. Steve probably also got twice the bonus and stock compensation that Dave did. Over time that starts to really add up. And if Steve is 10 years younger than Dave but way better, he's going to get promoted faster because we do whats best for the business not based on who had been around the longest. It's not unreasonable for the top of a range to earn a pretty large premium to the 'at/below average' guys. I will also say I think the ceiling at the higher ends is a lot higher for private work than govt, especially after you start getting into position where you are getting a heavy distribution of profit sharing/bonus/equity.
PENSION: I didn't read the specifics of your pension plan and it might be quite good, I will just say i have never been overly enamored with the whole pension thing (I have both perspectives, my wife is a teacher who has to contribute to a pension). It can take a LONG time to qualify for a reasonable benefit, it ties you to one employer/state/etc, depending on the terms (and if you want to voluntarily reduce the payout) it may or may not be passable to your children, the government can run into financial issues causing them to reduce the pension payout. Just a lot I don't really care for, and I feel that for financially saavy people (i.e. investors not spenders) if you take the difference in compensation and consider your bonuses, equity, etc, you can do just as well socking money away for yourself with a lot more flexibly. For myself we will be FIRE well before I would ever qualify for a pension, helped largely by me rising in the company and earning a good deal more in compensation than I could get switching over to a DOT now. Just my 0.02.
I was also going to write something about marketability as I am directly responsible for hiring my team so I have done a fair amount of it, but I ran out of time. The short version is that for senior engineers I'm much more likely to heavily consider design experience because that's how we go about making money. Field experience gives nice well roundedness and can absolutely make people better engineers but at the end of the day I make money by producing technically correct design plans in the most efficient manner possible, engineers that are experts in design usually accomplish this better (though I am in the design side of the business so it's about what you'd expect, not a huge shock). I agree with the other poster that those with primarily field experience will likely find themselves more likely to work CM or for a contractor...this isn't bad its just different.
Good luck