Mike, I would call Vanguard they offer free advice. There are several calculators on the web that I just used recently to figure out whether rolling over my traditional IRA into a Roth would be worth the $8,000 tax.
My situation is different due to age and withdrawal year. I have many many years to go before officially qualifying at 59 1/2 withdrawal age. I calculated the difference and it will save me over $40,000 to convert to Roth vs. keeping it traditional, even though initially I have to pay taxes on the conversion. But in your case, already at 50, it may not be in your favor to pay the extra taxes.