Although what you have done appears to be just fine, I would take a completely different approach than what you have done. I would use one fund per account for the next while, but I would use different funds:
63% S&P500 Index fund (yep, put all of it in that fund)
12.5% Vanguard Total Bond Market
Her Rollover IRA
22% Vanguard Total Int'l Index fund
3% any single fund you want (REIT, small-cap value index, or extended market index)
I would not worry have everything "perfectly" balanced at all. If you felt you need to rebalance, I would probably use "her Rollover IRA" at Vanguard to do so.
I think you will eventually come around to the idea that you might want more than 10% in fixed income.
There are many other possibilities. For instance, His Roth could be a single fund: Vanguard Total Int'l Index fund. Then Her Rollover IRA could be the bond fund plus another fund or two. And all rebalancing could be done in Her Rollover IRA.
His401(k): Mix S&P500 and Explorer for US equities
HisRoth: Total Int'l Index fund (set and forget mode)
HerRoth: REIT (set and forget mode) or Total Int'l Index fund.
HerRollover: All Bond fund, or Bond fund+REIT or Bond fund plus anything else for rebalancing.
It's all about short-term opportunistic rebalancing due to a short-term change in one's asset allocation, uh, I mean opportunistic rebalancing, uh I mean rebalancing, uh I mean market timing.