We had a great experience staying at Elvira's cocoon studio. Compact but definitely an interesting place to stay with wonderful sunset views from her doorway/ terrace. Elvira was friendly and accommodating to all our needs - even providing a lovely carafe of wine to enjoy the sunset. The wifi works perfectly from the terrace though naturally the signal is weaker in the cave itself:)
Advice on the ports - the apartment is in firastefani - the town next to fira/thira - the capital. Most of the nightlife, restaurants etc stretch between the two though expect plenty of steps. We got a taxi from the port from one of the travel companies costing 26 euro - but on the return paid 15 from a rank. My advice - try a taxi company directly or haggle!