Let's start in Athens where you arrive to pick up your bike. Catch the Metro at the airport for about 10 Euros and head for Syntagma Square. I'd suggest MotoRent where I always rent my motorcycles...they're the best!  MotoRent has a great selection of adventure bikes that include Third Party Insurance. Be careful funneling through Athens traffic...keep your head on a swivel and watch your mirrors! If you stay on the mainland, head for Marathon, Thermopylae or Delfi which are closest and worth the ride. If you're heading for the islands, you're going to ride to Piraeus, Killini or Patras for your ferry. I prefer the Ionian Islands and catch the ferry from Patras.

I usually stay at the Athens Backpackers Hostel for a night before setting off with the bike. I travel solo and it's nice to have a beer with fellow travlers from all around the world instead of sitting in a hotel room alone. Plus, it's close to MotoRent and in the safest part of Athens.