We actually tackled the first carpentry project well before the solar/electrical stuff because it would dictate the size and arrangement of most the other projects. Our original plan for the bed was a non-convertible design that would have taken up the entire rear of the van and provided a lot storage underneath. We framed it out and quickly realized that we did not like being boxed in to the small area toward the cab with no easy access to the rear doors. We found the inspiration for the design we ended up using on several websites, one with tons of detailed info and photos. We just had to figure out how to adapt it to our space. We already had the mattress (queen length by full width, cut in half lengthwise), so it had to fit those dimensions in both sofa and bed modes. Advanced algebra ensued. It turned out great, but we would make one major change if we did it again - As it is, both mattress halves must be removed in order to access the storage underneath. To make that easier, we would move the hinges out to allow one mattress to rest against the wall while lifting the base. Next time!
We got serious about the galley cabinet - We watched youtube videos on how to build a proper drawer, borrowed a contractor's table saw, bought a pocket jig, etc. It shows because the cabinet turned out really, really well. (It didn't hurt that we basically lifted the entire design from SprinterVanDiaries. Thanks guys!) The galley seemed so easy that we were super anxious to start on the big cabinet across from the bed.
Unfortunately, the big cabinet would have to follow a lot of curvature (front to back, floor to ceiling) across a large area. Even though we thought we were accounting for it, a couple of novice carpenters like us were likely doomed from the start. We also had lots of small setbacks (mis-measurements of doors, hardware challenges, etc.) that turned this project into a bit of a slog. When we finally got ready to install it (which required disconnecting a lot of the wiring since we built the cabinet around the electrical setup), it was not the tight fit that we hoped. But it's all fully functional and provides tons of storage, so it's good enough. (Again, deep breaths.)
Just a few more details to take care of (navigation, sanitation, recreation, etc.) and we should be ready to hit the road!