A quick follow-up for posterity, now that we're back... Everything's great, I'll post a real trip report with pics and first impressions later, but to wrap up this thread about what to bring...
I packed a below-minimum set of tools beyond my pocket knife, but they turned out to be redundant. The Sprinter's tire-change kit includes a couple screwdrivers.
For some reason, I thought SMB installed USB sockets up the wazoo, but the many 12V outlets throughout the van were all cigarette-lighter-shaped, so I wish I had brought a bunch of plug-in converters. There's one USB socket in front of the steering wheel powered from the starter battery, though.
We really should have bought leveling blocks at SMB, or had them delivered. At first, I didn't think we needed them (we tent-camped on slopes all the time, and it's not like we have any appliances that don't work on a slope), but I didn't anticipate the shower drain being above the shower pan, and trying to cook on non-flat countertops. Then, we could have bought them on the road, but after frustrating trips to WalMart and Autozone, we decided to soldier on without them.
My (bulky!) collection of fleece and polypro turned out to be completely unnecessary. Another habit from tent-camping, but since we wanted to test out all the systems, we regularly used the Espar diesel furnace to stay toasty at night.
Didn't bring a torque wrench. SMB insisted we didn't need a re-tightening, since we got the stock tires, nothing special.
It might have been useful to bring a funnel. We didn't really have any way to manually re-fill the water tank, but since we camped very conservatively in established campgrounds, we had frequent access to "city water" to top off with.
If not for the bulk, it would have been good to bring a sleeping pad. We bought a mat at Dick's on the road, since there's some slightly lumpy ridges sleeping width-wise on the unfolded dinette. The platform bed is smooth, but also benefits from a little extra padding, depending on your taste.
As for things we brought that came in handy, the pair of headlamps were crucial, not just for wandering around in the dark but for finding valves in the back of the cabinets! We brought the bare minimum of cookware, a pot, 2 bowls, not enough spoons, bought a stack of paper plates on the road. The tiny camp stove worked great, although I was always nervous that it would tip over, and of course we couldn't bring fuel on the plane and had to buy it at Dick's. Glad we brought several water bottles, one squirty bottle particularly handy for rinsing hard to reach spots in the portapotty.