I've been there numerous times, it is a great place. There's a few good restaurants in Keel including a very nice Chinese. As regards places to go, I recommend Keem Bay beach, doing the Atlantic Drive, the deserted village near Keel. There is also a number of art galleries around Keel. The scenery in Achill is beautiful so really no matter where you are you can't go wrong. The beaches on the north side of the island are very nice too and you can see the sun setting into the ocean from the right spot on them which is always a nice sight. The local rambling sheep always provide some entertainment as well.