Suspend seemed to work out-of-the-box. I’m not sure how long the battery would last in suspend; the 12 hours estimate was with the screen on and wifi on, just not actively in use.

I just set up hibernate; since I don’t care about hibernate, I didn’t set up my swap partition large enough. Using a swapfile instead is slightly trickier but still pretty trivial. The steps listed here worked fine: https://askubuntu.com/a/1367244