Well, if I end up at 80/20 and use 4%, that would be 20 years in stocks and 5 years in bonds, and then the 15 months would be on top of that.
My rough plan using ASCII art (numbers are very rough):
taxable (2 yrs)
^
| transfer as needed
V
Traditional IRA -> Roth IRA -> savings -> checking -> spend
(20+ yrs) (~7 yrs) (15 mo) (1 mo)
Numbers in parentheses above represent rough sizes in terms of monthly or yearly expenses.
Traditional IRA will contain the 20% VBTLX.
Balance of traditional IRA and Roth IRA and taxable represent the 80% in VTSAX.
I'll do a conversion from traditional to Roth in December each year.
I'll do a withdrawal from Roth to savings in January each year.
I'll set up monthly transfers from savings to checking that will become my monthly allowance.
There are a number of other pieces of the puzzle, large and small, that I've left out for simplicity.
I have slowly been putting together a plan in a separate Word doc that is currently 4 pages long and covers goals, transition plan, income, spending, investing, living, and contingency plans. Under transition plan there's a section on research I plan to do, and I'll add Dr. Doom's series to the list.
My basic bond question here belies the fact that I've actually done a lot of research and reading over the years. I've forgotten most of it over the past five years or so as I've just had my head down hammering away at kids' college funding, debt/mortgage payoff, maxing 401k, maxing Roth, income increases, etc. I hit basic FI about a year ago and so I looked up and started looking seriously at where I am rather than just from a theoretical point of view and sort of letting the reality sink in.
One thing that is not readily apparent is that for Mustachians who are saving 50% of their income, you can hit FI and then blow past it pretty quickly. The analogous imagery in my mind is of those submarines that surface with full up on the bow plane - breaching the surface is quite quick and, um, emphatic:
https://www.youtube.com/watch?v=JrU0bYq7KPQ#t=27This is especially true if you happen to hit FI in the midst of a market upswing, as I was lucky enough to have happen to me.