Sorry for the delay in answering your post, Kelkel. Herculaneum and Pompeii both open at 8:30 a.m. local time. You will have to pay 11 euros per person to enter each site. The better option is paying 20 euros for a pass that allows you to visit Pompeii, Herculaneum, Oplontis, Stabiae, and Boscoreale. This will save you 2 euros per person. Herculanem is nine miles from Naples, and Pompeii is fourteen miles from Naples. Being sister cities, they are relatively close in proximity. If you want to climb Vesuvius, understand the following;
1) The base of the mountain is easily accessible.
2) Wear comfortable shoes and bring water!!
3) When I climbed the mountain, it was a dusty, gravel road. (That may have changed since then)
4) If you are in relatively good shape, the round trip should take a little over three hours.
5) Vesuvius is no small hill. She is 4100 feet high.
6) Most important... she is still considered an ACTIVE volcano. She last erupted 1944 but she still emits smoke and geothermic heat.
7) There are toilets which will cost about half a euro.
8) 3/4 of the way to the summit you will need to purchase a ticket (price I don't remember, but not much. This allows you to continue up to the rim of the crater.
9) On the way back down, purchase some wine made from local grapes. Pretty good and fairly inexpensive. Remember, do this on the way down.
10) Depending on the date of your trip, it can often be cool and windy at the summit. You may want to bring a light jacket if you are easily chilled.
11) Sunscreen, sunscreen, and a little more sunscreen.
Enjoy and have fun... it's a great daytrip. Even better when it is a clear day. Awesome views if you are lucky. Most people know of her August 24, 79AD, eruption that destroyed Pompeii and Herculaneum. She also erupted in December 15-16, 1631, killing over 4000 people.
While climbing you will begin to understand her awe inspiring power and the respect that the mountain still commands to this day.