how big is the galaxy?

We were reading a Calvin and Hobbes comic and Lijah got interested in the size of the galaxy. I let him know that I could look it up and tell him, but it wouldn't be a meaningful number. He still wanted to know. So I started typing into my phone, and read out the Google suggestions as they came up. "Size of..." gave "size of queen bed", "size of king bed", and "size of twin bed". "Size of the..." predicted us to be wondering about the sun, the moon, or the earth. "Size of the g..." gave us "great lakes", "grand canyon", and, finally, "galaxy." Reading the wikipedia page we learned that the Milky Way galaxy is between 170,000 and 200,000 light years across; a light year is 5.88 trillion miles; so in units we can comprehend, the diameter of the galaxy is somewhere in the neighborhood of one quintillion miles.

"So," said Lijah, who never misses a trick, "it's bigger than a twin bed?"