Hi from someone in a similar situation (50/25 yrs of practicing, but not in gov't, and not quite as desperate).
What I do when I feel like you do is sit down and run my numbers. Looks like as of today, you'd have about $7500/mo to spend (I wouldn't count on your wife continuing to work given the issues you mentioned with her job, but obviously talk to her about whether she would want to continue working in some form and thus would give you more income to play with). How does that compare to what you'd like to spend in retirement?
One idea that I got from this site that may work well for your situation in particular is the idea of "buckets" of $ for a certain period of time. Yours could break down something like this:
Bucket 1: 52-55: Assume expenses are comparable to where they are now (X), because you still have kid at home. Income is A (your pension). Bucket 1 = delta between your pension and your expenses (X - A) x 3 years in this period.
Bucket 2: 55-59: Assume higher expenses (X + Y) because now you have college tuition. Bucket 2 = [(X+Y) - A] x 4 years.
Bucket 3: 59-62: Assume lower expenses, because college done and kid out of house (X-Z). Bucket 3 = [(X-Z) - A] x 3 years.
Bucket 4: 62-67: Assume same expenses (X-Z) but, higher income because of DW's pension (A + B). Bucket 4 is now [(X-Z) - (A + B)] x 5 years
Bucket 5: 67-90: Assume same expenses (X-Z), but higher income because of DW's pension and your SS (A + B + C). Same math -- Bucket 5 = [(X-Z) - (A+B+C)] x [# of years] [note that you may get into negative numbers here, if your expenses are less than your projected income -- this is good]
Etc. Note this setup is pretty complex -- you could also just use some simpler assumptions and fewer buckets [e.g., I see your mortgage goes away shortly before your DD goes to college, so that might all be a wash]. But the general idea is to calculate these different buckets, each of which represents the total amount of money you need over a specific period of time. And then you back-calculate how much you need invested *today* to cover all of those buckets, and compare that against your current savings.
So for ex, for your first bucket period, say your current expenses are $6500/mo. Since your pension is $5500/mo, you will need an extra $12K/yr x 3 years = $36K to cover that period. Since Bucket 1 starts today, there's no real net present value, so basically you need to set aside $36K out of your $600K stash today to cover the next three years.
So now you have $564K left. For the next bucket period, say your expenses go up to $8500/mo. (college). Now you need $36K/yr x 4 years, or $144K invested. But you don't need that until 3 years from now. So you can back-calculate (based on conservative assumptions) the amount of $ you need today to make sure you have $144K in 3 years. Say that's $120K. So you need $120K out of your remaining $564K to cover that 4 years. Now you have $444K left.
Basically, rinse, repeat for each bucket (note I am ignoring the growth of your stash within each bucket period for simplicity's sake, but you can calculate that in too). So if you get to the end and discover that, say, the pensions + SS are enough to cover you from 67 on, and your stash is enough to cover the difference from now until 67, you are good to go and may FIRE when ready. OTOH, if you are short, this can give you a really good idea of where and why and exactly how much more you need. Personally, I found this much more helpful than the standard 4% rule, as we plan much higher expenses for @ the first 10 years of retirement than after.
It's probably also more accurate to do it backwards - if you start with the furthest-away period and move towards the present, that tells you exactly how far away you are. E.g., if your current investments will get you from 58 until you die, then all you need to do is fill the bucket that covers 52-58. For me, that helps focus, because you can really see how additional savings will cut weeks or months off your work life.
With respect to the emotional issues, that I can't help with, because I'm right there with you. The only thing that I know is that it always works better when you are running to something than when you are running away from something. My personal plan between now and FIRE is to spend the time figuring out what, exactly, I am going to do to use my time productively and in a satisfying manner once I pull the plug on the career.
