Language could be a problem if you're really out of the way, but most hotels have English-speaking staff. I would strongly urge you to learn at least a few words in Turkish - "good morning, thank you" stuff. It's true everywhere that a few words break the ice and garner favourable attention but especially true in Turkey where people are especially hospitable and friendly.

As written above, the bus services and flights are good options. I'm not so sure about driving; I've driven there extensively but it's not, shall we say, for the fainthearted! It's anarchic and chaotic, though far safer and more structured than twenty years ago when I first worked there. Cost wouldn't need to a barrier to hiring a car.

I understand the temptation to see everything and go everywhere but I would strongly suggest that you are selective - part of being in Turkey sould be about the culture and the people. You simply won't get that on a whistlestop tour of big attractions. Istanbul can reasonably lay claim to being one of the worlds 1/2 dozen greatest cities, though Capadoccia and Ephesus could probably be covered in a day each. Bear in mind that Capadoccia is quite remote from other sites (Ankara isn't worth seeing, IMHO). Ephesus, however, is near Izmir, is on the coast and might be combined with say, Bergama (ancient Pergammon), Truva (Troy) and the Dardanelles.