First timers more questions

We arrive in Venice and we plan to take the Alilaguna Orange line to our accommodation, which is suppose to be very close to the orange line. Should I purchase these ticket online before we leave?
No need to buy ahead, there is no cost advantage and it is basically like a bus ticket.

Then we will fly from Venice to Naples. I believe we have to take the Circumvesuvia to Sorrento, which is where we are staying.
You first need to get to Napoli Centrale from the airport, Taxi would work $15 to $20, bus would be less, it seems there is a direct bus as well. From there, yes the Circumvesuvia, from the adjacent station.

We have a Mondo tour for Pompeii one day so I know we need to take the Circumvesuvia to Pompeii but if we also want to do Mt. Vesuvius, how would we get there from Pompeii and then back to Circcumvesuvia to get back to our hotel in Sorrento?

Do some searches, there are buses that run from the Pompeii station, and I believe from one of the entrances to the Pompeii site up to Vesuvius. A taxi would work as well.

Also a question about Euro's. Should I get them before we leave or wait to get to the airport in Venice?
Depending on your bank, get some euros (couple hundred) before you leave, then use an ATM (search for tips on ATM usage in this forum, plus in articles on this site) to get euros as you go.

Also, I just got a capital one venture card for the trip. What are the advantages to using this card. Do the restaurants in Italy take cards? I know the tours I need to pay cash.
Not privy to the details of the card, but if it offers no foreign transaction fees, then it is good. Nearly every place takes credit cards, use like cash for all but small purchases.

The previous poster gave you excellent advice. I agree with getting a few hundred Euros ahead of time. Yes, you’ll pay a premium but we are talking $10-20, trivial when compared with the cost of your trip. Yes, there are ATM’s at the airport but the last thing I want to do is land with no currency and find an ATM when I’m jet lagged, fish out the debit card, etc. The Capital One card will be widely accepted. I use it exclusively in Europe. Do carry another credit card as a backup in case you lose it or it’s compromised. Let your credit card companies and your bank (the one whose debit card you’ll be using) know about your travel plans. Just call the numbers on the back of the card.

Have you purchased your airline ticket between Venice and Naples? Personally I would take the train. It would be a lot easier than flying and potentially faster. I always bring a hundred euro from the US so I can easily get from the airport to my hotel without any additional hassles. The next day hit a local ATM and get a couple hundred more for the next few days. You do have a debit card?? Bring two tied to two different accounts. Master and Visa credit cards are widely accepted. It would be difficult to do both Mr. Vesuvius and Pompeii in the same day. Too much ground to cover.

Good advice on the travel particulars above.

On money: Basically everyone accepts credit cards at this point as long as it’s a CHIP & PIN card, which a newly issued credit card will be these days. However, there’s often a small upcharge by the establishment to cover the fees they pay to the credit card companies. They prefer hard cash. You’re paying a fee to draw cash though, so personally I feel like it’s a wash for the added convenience. Don’t sweat it.

You may be asked if you want to pay on your card in euros or dollars, explaining the exchange rate they are offering that day. I just pay in Euro, that way you know you’re getting your bank’s rate and the standard fees. Someone else may have a better explanation on this, but it’s worked for me so far.

It’s handy and comforting to have some euros in your pocket when you land, but you do not need hundreds of dollars worth. A hundred at most will do. Be aware that it may be more expensive to get euros before you leave. My own major bank in a major city uses a “retail exchange rate” to buy hard currency that’s CRAZY HIGH, like almost $1.50 = 1€!!!

If you have already bought plane tickets into Naples, check out the

Curreri bus which runs from the airport to Sorrento -- air conditioned, comfortable seats, luggage goes underneath the bus. Bus ends up the same place in Sorrento as the Circumvesuviana, but with less hassle.