, it depends. How close are you to hitting the income limit for Roth IRAs? See here
. Rolling an old 401k over to an IRA will mess with the
Backdoor Roth IRA
option because of the pro-rata rule.
How good are the options/expenses in her (soon-to-be) old 401k? If she has at least $5K in the plan, she can keep her assets there.
How good are the options/expenses in her (soon-to-be) new 401k? (Although generally with Vanguard they should be fine.)
Whichever option you choose, you don't have to do it immediately. Make sure you know what all the choices and costs are/would be before you decide.