So for 3 1/2 "member" years I am at 251 nights and 1,142,301 points. Well, I guess on the positive side I still have (just) enough years left before I retire to get the 12 in, and I should be able to meet the other Lifetime Platinum requirements.

Well, for 3 1/2 years it appears to me you are doing pretty well. You have about 40% of my nights, and almost equal to me in points - with less than 20% of my "time in".
(20 membership years, 615 Elite nights, and have earned 1,188,034 lifetime points.)
I see no way I can hit Plat as I expect my travel to end within the next 2 years or so. I WOULD like to hit GOLD, so if anyone can share their secrets as to how to do it inexpensively I would love to hear them.
I mean, I could care the least about free breakfast NOW, but when I am on my retirement pittance.... it will be another story

!!!