I've been riding there a few times. The wind isn't that bad really, though of course you can have bad luck and as the landscape is so open and flat, there's nothing to block it really, so it's free to blow from the sea.
Avoid the the biggest roads, like the 4/E67/Via Baltica along the coast south of Pärnu. The smaller roads are mostly very qiuet, from what I've seen.
The islands are nice, might be pretty quiet now before the tourist season. There's castles and everything. I ended up in a monastery having tea with a greek nun there too once, was interesting. As are the ferries, simple old things.
The abandoned prison and mine in Rummu are interesting. Kind of an unofficial tourist attraction.
There's lots of interesting little villages. People are moving away from the countryside it seems, so rather empty if you choose smaller roads. Smaller roads tend to be gravel occasionally.