It takes about 5-6 hours to drive the entire south coast of the island, from the ferry witch lands at the most eastern part of the island it´s about 7 hours. You can drive around the island in two days or one very long one.
Road No. one has been opened again after the eruption so that´s no problem and the south coast has better roads then the northern part.
Recently, and last summer the east coast has had the most wind with wind over 30knots quite frequently but that can change, just depends on pressure systems on any given time.
From Eyjafjallajökull to Vatnajökull (south coast) the coastline can have massive shore breaks that can be very tricky. That´s not a problem in general on coastline with fjords.
Reykjanes peninsula (south of Reykjavík) has tons of wavespots and you can find spots in any given wind direction with in a 30min drive.
If you like sailing with 6m or bigger there are spots on the norther part of the island that have very predictible wind coming in and out of certain fjords at certain time of the day.
There are about 6 windsurfers on the island, 5 kiters and 15 surfers, you will not find a crowded beach but then again no lifeguards either.
some surfing on the north coast this winter:
some windsurfing in Reykjavík last spring, 5min drive from the center:
Some windsurfing on a tricky day at a tricky spot on the Reykjanes peninsula (30min from Reykjavík)
If you need any more info just ask again or i can give you my email, if you come to the island don´t hesitate to contact me and i can help you out.