OP here! Thank you all for your replies!
I think I need to work up the gumption to try a little harder on getting this online savings account thing to work. Both Barclays and AmEx took all my info (like, ALL my info - including SSN) and then I got error messages after submission. Both times! And it was outside their customer service hours, of course, because that's when I have time to sit down and do this kind of stuff.
I have a followup question: Do any of you use Fidelity's Cash Management? What has your experience been?
I did a little reading yesterday, since Fidelity Spartan Index Funds are one place we are considering for these funds (even I get a little whiplash at the thought of going from no-interest savings account to the wild wild west of index funds) and they seem to offer a savings-account-like structure that is FDIC-insured. The closest Fidelity storefront is about 20 miles away - doable in a pinch, for sure.
I guess I am old - I seem to want a place to go, people to see. It's really hard for me to imagine clicking a few buttons and watching my hard-earned (well, in this case, inherited) nest egg float off into the ether.
In terms of timing, it completely depends on my spouse's job, since we currently live in employer-provided housing. A change could come as soon as six months, or we could be here for two more years, or four, or six, or even more. At this point, I am thinking closer to two to four years than the six month or six+ year scenario. But without knowing, it makes me want to clasp that money close to my chest!
Going by MMM's approach, we probably have "enough" already. But my spouse lives to work, and it's hard for him to imagine ER. So instead, I've been talking about FU money and FI in general.