My understanding is to get money out of my 401k without penalty tax free prior to traditional retirement age I can convert my traditional 401k to a rollover traditional IRA. I can then convert a portion of that to a Roth IRA every year. The principle will then be available tax and penalty free to withdraw from my Roth IRA after 5 years.

On that conversion from traditional IRA to Roth IRA the pro rata rule applies if you are only converting a portion of the balance instead of the full amount. I'm trying to understand if there is a way to avoid that by only rolling over some of the traditional 401k balance at a time.

It's possible I'm fundamentally misunderstanding something too.