Marshall: Don't worry, we'll get out on the road, it'll be just like old times.
Future Ted: [v.o.] It wasn't.
[flashback to one of Ted and Marshall's college road trips:]
Both: [singing] But I would walk 500 miles And I would walk 500 more.
[jump forward to Ted, Marshall and Lily on the road:]
Lily: Sugar snap pea? Pea... That reminds me, I have to pee.
[flashback to Ted covering Marshall's eyes as he drives the car:]
Ted: Okay, straight, straight, straight. Now, wait, a little to the left. We'll pass a state trooper.
[present: Ted is asleep in the car]
Lily: Ooh, punch buggy yellow! [hits Ted's arm]
Ted: Ow!
Lily: Yellow, that reminds me, I have to pee.
[flashback to Ted going through a toll booth naked in 1999:]
Ted: Thank you!