What I do after multi-hours races is walk around a bunch before either driving home or sitting for extended amt of time. If it's an "away" race, I'll do some light hiking the next day (few miles). (I'm on trails anyway, and I generally plan on a 3-day trip - drive there, race, recover hike, drive home) If I feel really sore that night, I'll take a cold bath or shower at least on the legs and maybe pop one aleve. Eat well the first night - replace carbs and get protein for healing. Hydrate if you got behind. (I forgo the cold bath if I was in cold rain or snow with extended time.) What I do in those first hours and day(s) has a lot to do with quickness of recovery.
Then stay reasonably active with light activities the rest of the week - walking / hiking, biking, swimming, xc skiing, whatever works. Keep the blood moving, and keep body moving so things like tendons recover in a normal configuration rather than a tangled mess. (last comment is really more from an injury perspective, but I think the general idea of keeping some normal motion for appropriate healing is still good) I avoid running until it feels right. I might try my first run for 5-10 min, and if it doesn't feel right, I just revert to walking.
