I won't give a play-by play of how we did the baseboards and crown, because I'm sure we didn't take the easiest or correct route, but I will give a few tips and some before-and-after shots.
Since we're getting new carpet, the question arose of whether to put up baseboards before or after the carpet. Googling basically gave the answer of either, but it's a better idea to do the baseboards first. I also figured I could be messy while painting them, and not have to worry about painting the around carpet fuzz.
We also discovered that the floors sag almost an inch in places. Not enough to notice while walking around, but how do you place a straight board on that? Turns out carpet will puff up to take up the space, so it's more important to be sure there's enough room everywhere to jam the carpet under the baseboards.
Those questions answered, we got to work! The cuts were pretty easy, and the nail gun the neighbors lent us (thanks guys!) was a dream.
Then we moved on to the crown. I bought a Kreg Crown-Pro Crown Molding Tool to help us manage the crazy angles. It did the job, but it holds the wood in such a way that our 10" saw wouldn't make the whole cut. Tommy's grandpa came to our rescue though, and lent us his 12" saw.
After that hiccup, cutting the wood was fairly straightforward. The Kreg Crown-Pro came with a handy booklet that walked us through the process, and we never even made a wrong cut!
When we went to hang everything, some of the corners weren't amazing, but caulk filled them up OK and you can't tell anymore.
One tip for hanging - we made little pieces to match up in the corners with the piece we were hanging. These helped us get the angles right and ensure all the pieces were going to fit together OK.
For the little guys that finished off the crown near the closet, we attached them to the longer piece with wood glue, let them dry overnight, and then nailed the long piece to the wall.
Tommy caulked all the cracks, and filled the nail holes with spackle.
Now it's time to get a final coat of paint on everything!