...not in Naples but surprisingly accessible from Naples!
Can you breathe at 19340 FT?
Shah tours is the guide company that we used. We had five people (10 porters and 3 guides). Average cost $910 +tip (~$90) = $1000
The tour guide compay charged us $70 for a ride from the Airport to the hotel. I am sure this is negotiable, since everything is in Africa. We were all very happy with Shah tours. Our head guide was named John and we highly recommend requesting him. He was very good about looking out for the well being of everyone in our group.
We took the Marangu Route and spent 5 days on the mountain. First three night you stay in huts then you begin the summit on the forth day at midnight. You will reach the summit at ~0700 on the forth day. You will hike back down to the second hut that same day and then out of the park on the fifth day. This route is called the "coke-a-cola" route, because of the huts and easy hiking. There are harder routes up the mountain. You will be staying in tents rather then huts and if you go up the MACHAME ROUTE (Whiskey route) you will require one more day on the mountain. The final summit day is easier on the Machame Route vice the Marangu route due to the approach to the summit. I still recommend going up the Marangu route. We had rain and it was nice to go inside the hut and dry off.
After the mountain we took a two day safari after the hike. We explored the Tarangire and Goragora Crater National Parks. It was a wonderful time!
We used Kessy brothers tour guide (http://www.kessybrotherstours.com/progs2.htm). We paid $175 a day which we negotiated in Moshi after the hike. Shah tours wanted $550 to book in advance.