4) Compression
There’s a well known saying that every cyclist should remind themselves of from time to time: “never stand when you can sit, never sit when you can lie down, and never stay awake when you can sleep”.
Take every opportunity to stay off of your feet. I always use the hotel stairs unless I’m thinking “recovery” then it’s the lift every time. Elevate your legs to improve blood flow around your body and so that your heart is under less stress trying to pump blood against gravity. And finally, despite being unable to bring myself to use them on the bike while riding, try using compression socks at all other times.