Rather than roll over a big amount, why not just start contributing annually to Roth accounts?
At your income level, ~100k currently, you're solidly in the 25% marginal federal bracket (plus a bit in MN state tax and SS/medicare). Looks like in 2016 you are very likely to be in the 15% bracket. If you think you will stay in the 15% federal bracket thereafter, it may be easier/less headache to simply start contributing more toward a Roth going forward than to convert traditional to Roth?
Other complications: your employer (current) may not allow conversions, or there may be other issues. Check with HR and read through your disclosures. Be warned, I mentioned just changing your allocation to Roth going forward because this could take a lot of effort to get clear on your employer 401k plan rules.
At the end of it all, you're in an income range which over a long period of time is unlikely to be the target of significant tax increases. Of course, anything could happen, but just something to consider. Since no one knows what the future holds, the best way to deal is to have a bit of both. If I were you, I'd maximize my Roth accounts first (11k combined starting in 2016), and then put as much as possible in your 401k.
Things could change depending on your estimates of likely future income. If you think you'll stay in a similar range (inflation adjusted), then it won't make too much of a difference. If you see your income doubling or greater, then more Roth now might be helpful.