Ok, I've been doing some researching while waiting for the time I can start calling. I may have found a tax professional in my own town that has a good reputation (yay!)
I still don't understand one thing - if we roll our Vanguard 403b into a Roth, is it the same plan (the VANGUARD INSTL TARGET RET 2020 FUND) with the same growth rate and risk rate, just with different tax implications? I can't seem to find an answer for this question. I've looked around the Vanguard site, too, but if the answer is there, I can't find it.
I feel pretty safe with this Vanguard account that we have, and am cautious about changing it.
The "INSTL" in "VANGUARD INSTL TARGET RET 2020 FUND" is short for "Institutional", meaning you can only own it in an employer's plan. If you roll the account over to a Traditional or Roth IRA, then they will probably* liquidate this fund and you would then reinvest in a similar fund that's open to individual investors. "Vanguard Target Retirement 2020 Fund (VTWNX)" should be pretty much the same fund, but for individuals.
* If both accounts are held at Vanguard, then it's possible they might allow you to keep the institutional shares. You'd have to ask them.