Lefkas is not very quiet, being a big sailing centre (especially Nidri) and it is a good centre for exploring the region, up as far as Parga. Fly to Preveza.
I have always thought of Samos as a green island and it's certainly big enough to keep you occupied for a while, especially if you take a trip across to Ephesus. Plenty of roads to explore. Fly direct.
Symi (my favourite) is certainly small and has only two roads but is the best place to sit in a bar or taverna (lots of them). Look at symivisitor.com for a map of the beaches and lots of photographs. Fly Rodos.
Lesvos is again a large island with plenty of places to explore. Molyvos and Petra spring to mind but you can find lots of reports on this site. Fly direct.
I've only been to Lemnos for 20 minutes (refuelling) so didn't form much of an opinion about it!
How about the Isle of Man? TT, perhaps? How fast is your moped?

Consider Naxos, a bigger island with a lively main town (Naxos, would you believe) populated with people who don't mind taking ferries from Piraeus to reach a good destination. Loads of excellent sandy beaches, some very remote. Good Hora in main town, two unspoilt big villages to visit inland. Good Greek nightlife, and a robust presence of more adventurous holidaymakers from northern Europe.

If Naxos is too big, consider Syros. Small island, numerous sandy coves along the west coast. It's a ferrying centre (capital of the Cyclades) with a population of about 30,000 mainly Greeks. Ermoupolis, the town, is lively, mainly with Greeks plus some some international transients and some of the more adventurous tourists who don't mind catching ferries.

Have a look at my website (non commercial) for more information. Although it's designed to be useful for visiting yotties, there's quite a bit which may be useful to you. Go to the 'Sailing/Greece-Details section.

JimB
http://www.jimbaerselman.f2s.com/

Lesbos is your best bet, Molivos is the place, could cross section of bars and restaurants.
Go to Molly's Bar in the harbour, its like Cheers, you can't fail to make friends there.
Plenty of great deals on accom, check Galliano Rooms, British owned and cheap

Thanks, I will take a look.

Samos and Lesvos were on my list of possible others apart from Lefkas, I just thought the island maybe wasn't very 'green' and lush and maybe was too big for just 7 nights, I like an island I can get round easily on the moped. Kefalonia took some getting round in a fortnight and Lesvos is even bigger.

Heard good things about the island so will definately visit if not this year then on my list of next 3 island. So many to choose from.

Leah