Make sure you NEVER take possession of the money. Let the brokerage firms handle the transfers.
A private Roth IRA to private Roth IRA should be fine. If you start mixing in Roth 401K accounts, I think you can only go one way.
FIRE no later than 7/5/2016
at 56 (done), securing '16 401K match (done), getting '15 401K match (done), LTI Bonus (done), Perf bonus (done), maxing out 401K (done), picking up 1,000 hours to get another year of pension (done), July 1st benefits (vacation day, healthcare) (done), July 4th holiday. 0 days left. (done) OFFICIALLY RETIRED 7/5/2016!!