Ned's eyes lit up because that was a great idea and it made total sense - Peter wouldn't do any good if he was caught stealing a car and charged as a kid on a joy ride or whatever. "Wow, yeah, okay!" He nodded, eagerly filing away the suggestion to work on later. This is why Tony Stark was the best of the best.
"Uh, a couple days? Don't tell my teachers, but sometimes when the stuff they're teaching is boring I pull up stuff like this to work on."