So first, hi from a fellow 52-year-old. ;-) I am **not** the spreadsheet guy, so I am not the right person to go through that. But one thing that helped me plan all this out is the bucket approach, which I first got from someone here: basically, you divide your life into different financial buckets based on the different income and expenses you will have over a given period of time, and you figure out how much you will need to cover each individual period. Then you start filling up your "buckets" with you current savings, started with the furthest out, and when you get to the point where your current savings fill all the buckets, you're good to quit.

So to illustrate: for you, maybe the first bucket is 55-58, bucket 2 is 58-60, bucket 3 is 60-70, and bucket 4 is 70-95 (or however long you are projecting through).

Bucket 1 you are making say $25K for that three years under the PPRP program. Your expenses are $30K. Therefore, you will need $5K/yr x 3 years = $15K to fill that bucket. 58-60 you can't do PPRP any more, so you need $30K/yr x 3 years = $90K to fill that bucket. Then from say 60-70 you can draw the widows' benefit, figure out how much that would be, subtract from your expenses, multiply by 10 years. Then at 70 you can claim SS, so you add SS + widow's benefit to get your total income and subtract that from your anticipated expenses and multiply that figure by the number of years after 70 you are expecting to live.

Of course, you don't need all that money right now -- you will need to have $15K at the age of 55, and $90K at the age of 58, and so on. So once you figure out the individual numbers, you present-value that back to today. So maybe you only need $12K today to have $15K in 3 years, and $65K today to have $90K in six years, etc. Once you have the present values for how much you need now to fill each bucket, you add all that money together -- that's how much money you need today to cover each of those periods.

If you currently have that much in investments, congratulations! Your plan is set. If you are short, then you use your current investments to fill those buckets starting with the furthest-out period. So say you have $350K now and you will need $200K of that to cover your 70-95 period. OK, mentally allocate that to that bucket. Then look at your 60-70 bucket -- maybe you need $125K to fill that bucket. Good, that one is filled, too. Now you look at your 58-60 bucket -- you have calculated you need $65K today to fill that bucket. But now you only have $25K left. OK, well, now you know what you need: you need another $40K in today's money to fill Bucket 2, plus another $15K in today's money to fill Bucket 1 (55-58). So you need a plan to add that amount to your savings, which you can totally do. (Please note that all these dollars are totally made up for illustration!!).

FYI, DH and I did exactly this, because we are also older, and so we really only have a relatively short period of time before SS/pensions are available, and it showed us that we needed much less than the 4% rule would have suggested. So that might give you another way to evaluate the scenario as a reality check -- I bet you will be more than ok.