The Roth IRAs give you the flexibility you want, I'd bet - you can withdraw contributions at any time, so if you max those you've got 11K * number of years that you can use to smooth the income when you cut back, before having to jump any significant hoops.
Also - from the stated numbers you are around 100K gross, and to max both accounts would take 46K (Roth IRAs + 35K to Traditional 401Ks) of that, leaving 55K to live on / pay taxes. 7.65% for FICA + no more than 6% of gross for federal income tax leaves around 36-40K for health insurance and to live on - can you get by on 3 grand per month? If so, you can probably make this happen.
[Edited twice due to numbers typos]