Hello, a group of 5 of us are on a 2 week backpacking trip and will be visiting Greece the first weekend in September. We arrive in Athens on Thursday and are planning on taking a ferry later that day to (possibly) Mykonos for Thurs/Fri and then taking a ferry to Santorini on Saturday. A friend recommended using Hellenic Seaways. Is this a good/reliable option? Should we book these ferries in advance/online or is it safe to just book when we get to the ports?
Also, we are having trouble finding affordable/available accomodations in Mykonos so would be open to other island suggestions that offer some nightlife (not necessarily clubs, just bars/some young people) as well as great views, beaches etc. if anyone has any recommendations? We just want to make sure there would be a ferry available from that island to Santorini on Saturday though.