You guys are a riot. But on the issue of interstellar travel, you're all thinking too small.
Why abandon your star to spend tens of thousands of years on an interstellar spaceship when you can just take your star with you? You can make a low mass red dwarf out of existing solar system bodies that will burn for tens of billions of years and is relatively easy to move around. Collide Saturn and Neptune into Jupiter and you're most of the way there already, and the collisions can destabilize the orbits and send the new star on its way to visit our neighbors.
And that's without even bothering with contained fusion. That little trick would keep a whole moon warm enough for plenty long enough to make the trip. I've always thought the idea that starships would look like trucks to be too simplistic. For trips that long, we need lots of mass. At least asteroid sized. A real home to take with you.
And why bother to stay very warm at all? Our fragile human bodies are well suited to life here, not there. Much better to transfer/transform ourselves into something more durable and well suited to the journey, with the option to transform into something else upon arrival. We just recently figured out birth control pills and now we can clone designer babies at will. It's almost too easy.
Humanity has been around, in roughly the same shape, for tens of thousands of years already. People had gross dirty sex, lots of women died in childbirth, everyone was a farmer, and you were lucky to see your fiftieth birthday. Then in the past two hundred year eye blink we went from discovering electricity to putting a live video feed on a Martian robot. Give us another thousand years and I guarantee you we'll have people on Pluto just itching to go out farther. Give us another ten thousand and they'll be arguing over how many interstellar ships to send per year.
This is the reason people want to believe in aliens. If intelligent life doesn't destroy itself, it is possible bordering in inevitable that it is currently exploring the universe and it seems somewhat perplexing that it is so hard to see it everywhere we look. It should be obvious, given what we know, and the fact that it isn't suggests that intelligent life might not be as stable and long lived as we would like to believe. Or it's really good at hiding, or we're really bad at recognizing the signs.