My only idea of day trips from Naples were the Amalfi Coast (which I missed, because I'm a huge trol and I managed to get lost in Sorrento looking for the bus. I'll tell you this story some other time), and to go up the Mount Vesuvius - I mean, climbing to the top of a Vulcano sounds AWESOME!).
The weather was horrible, and after spending my first day closed in the hostel of Naples, I had to do something. I was still too scared to go to the center (stupid me), and the Amalfi Coast was not na option with bad weather, and because everybody told me to go to Pompeii, and after finding out it would stay a lot cheaper than going to the Vesuvius, I decided to go for it.
"Creppy!!! I want more!" This was were I got disappointed to discovered those where the only bodies at the ruins. Just two! And I'll be honest with you, I thought I would see the bodies sill on the ground on the place those people got hit by the lava, and not into some boxes. Sorry, but it was disappointing.
Hop on the train back, after missing one for a few seconds, and got a funny ride as the two Italian guys in front of us were just way too entertaining. They looked like a couple of boyfriends, sharing the phones of their Mp3 and then having a fight in which one got very mad and the other was trying to apologize, it was hilarious! Ok, it doesn't sound that much funny now, but if you had seen the characters I'm speaking you'd be laughing right now. Just imagine a very Italian (Naples style) with his typical mustach and a shirt that was probably from when he was tem years-old - yes, we had a view of his belly the entire ride!
Eventually I said goodbye to my friend for the day, and I can say it made me feel a little lonely, because yes, I was again alone, and I was in Naples, but well, had to keep going and leave my fear behind or it would ruin my trip.
The entrance to the ruins is 11€ or if you're na European citzen under 25 you can just pay 5,5€ (pretty cheap!)