Twenty years, then ding: you wake from hibernation, stretch, yawn, dispense yourself a cup of coffee and then start going through the graphs and charts and readouts and error dumps and false-color images the computer has accumulated while you've been asleep.
Everybody else is behind you, between the crew module and the drive section, still asleep, cargo. They'll stay that way until you get to Epsilon Eridani.
It's days or weeks getting through all the data, and then you're back into hibernation again. I'd tell you you're not awake long enough to feel lonely, but it'd be a goddamn lie.