But are you seeking maximum tax shelters, providing for your kids' educations, or flexibility?
Do you have an HSA? If so, I would max that (if tax sheltering is an issue).
My next comment was going to be to do a Roth, but that doesn't seem to be an option for you. If there are options for you to contribute after-tax to your 401K plan, then convert to Roth through a "backdoor Roth" strategy (well documented on this site), then I would consider that in the future. But if not, I wouldn't invest after tax dollars in a typical 401K plan given the fees. You're better off investing it on your own and purchasing EFTs or index funds.
If kids' educations are a priority, I would give early and often to that category and at least rack up the state tax credits. Better yet, if you or your spouse may benefit from one in the future, start one for yourselves (you can always transfer the money to another beneficiary.) I have them set up for both my husband and I and this is one way we will fund our retirement fun. (We like school. What can I say?)
If flexibility is a primary concern, then I would start developing an unqualified investment strategy, which will be an important cornerstone of ER. I am questioning whether $70K in cash is excessive and could be better off working in the market (if even in a bond fund). Do you have access to a HELOC ("springy debt" as MMM likes to call it)? I guess the question is, what would you do to tide yourself over in the event of a shitastrophe? If the answer to that question is that you'd be forced to make major changes anyway (selling a house, relocating, spouse returning to work) then what you're really looking for is a low-cost way to tide yourself over til you can get your feet under you.