This ended up being way more annoying than expected, as are most home improvement project as I'm learning. The actual panels weren't bad since we could use the roller, but all the window sills, corners, and spaces between the panels were a huge pain. I was originally going to leave the trim and windowsills natural wood, but it looked funny so I ended up painting.
Primer is also kind of an awful thing. I really think the inventor of primer was kind of an a-hole who decided to make it an awful gray color that goes on totally unevenly. That way, when you're too far into your project to ever turn back, you keep looking around thinking "oh wow, this is going to look TERRIBLE."
That all said, it wasn't horrible. I actually find painting fairly relaxing. I sit in a chair thinking and writing all day for work, so it's kind of nice to shut my brain down for a few hours and just make sure I'm painting in the lines (and not dripping on the floor).
Here's some pictures of the progress:
See what I mean about the uneven-ness? I think this is normal after priming, and I've read it's just important that the whole surface is covered, not that it's covered evenly. Let's hope that's true, because I really don't know if I can handle doing too many more coats. We used Kilz oil-based interior primer which is supposed to be the good stuff, so hopefully it'll be able to block as much of the panelling as possible before we throw on a coat of white paint.
Even though it looks kind of ugly, I'm starting to see what the finished project might look like. We're gathering up odds and ends of furniture and I really can't wait to start putting everything together.