I've got some long overdue updates. Been dealing with rusted, seized, or corroded everything, which as you probably know increases the actual work time by about 3 times what you estimate.
After trying (and failing) to source parts in the US, I finally bought a big box of parts from a 206D enthusiast in the UK, including all the wheel cylinders, the clutch slave cylinder, and a variety of suspension bushings + ball joints. I used my time off over Thanksgiving to install the front cylinders and start on the rears. It took quite a lot of effort to get the stuck rear driver's side drum off, but got it off eventually and discovered the culprit was a broken brake shoe. I'll need to buy a new one, but at least the wheel isn't locked up any more!
I've finished stripping out the old camper interior and wiring. Discovered a useful access panel for the fuel tank sending unit under the carpet, along with a few pounds of nuts and acorns from a previous furry tenant.
One issue I've been confused by is the clutch. It's stuck disengaged, which means I can't get the van moving under it's own power. Since the hydraulic lines were empty when we got it, I'm thinking the clutch slave cylinder may be stuck. But reading through the operator's manual again, it instructs you to "lock the throw-out lever in the clutch housing". So now I'm thinking the PO might've done this before the van was parked. I need to take a closer look with the front wheels off again -- it's a pretty hard to access area.