Installation of the ceiling support panels is complete. I started installing the tongue and groove slats and ceiling lots as well. It was a bit tricky working around the shape of the van roof. Using the Cross-nuts (a.k.a. Plusnuts) worked well for securing the marine fir plywood panels. The panels have an inherent flex to them which made them much easier to install. Rather than try to fight with a single piece spanning the entire roof east-west, I used either 2 or 3 pieces (the three was because I was trying to use up some of the plywood that was used to ship the fridge.) Some modifications on 1" L brackets was also needed. I used a tap and die set to thread a hole on each bracket to 1/4" 20 t.p.i. so that I could use the same bolts to screw into the brackets and Cross-nuts. On the other side of the bracket a hole was enlarged so that I could use the same nuts to secure the brackets to the Cross-nuts I installed in various locations of the van. Most of the Cross-nuts went into the roof ribs but at the back part of the van there is no cross rib to attach to. In that location I installed Cross-nuts into the side and end walls so the modified L brackets could act as anchor points for the bolts. To install the tongue and groove slats I'm using 1" long #6 black trim screws. I wish they had come in a shorter length (1/2" would have been ideal) but they'll have to do and I'll have to be careful with wire locations and screwing (both the plywood backing and TG slats are 1/4" for 1/2" total thickness.)
Calvin here - after spending almost 33 years in education as a high school teacher, elementary teacher, and elementary administrator, it was time to retire! I did so happily and with no regrets; it was a terrific and fulfilling career. I do enjoy building projects as the design and building process is very therapeutic and you see a completed functional product in the end. Now to combine the build with another of Angela's and my passions - travel - is something we're really looking forward to.