The Skellig heritage centre on Valentia Island is a good place to go to after having been to the Skelligs to get more impression about the monks, birds or the lighthouse people who lived there.
But don't think the Experience is replacement for making the trip over to the rock itself! You can go on a boat from the visitor centre which brings you around the Skelligs - but without actually stopping and getting off the boat... if you ask me don't do that! Go on a proper boat trip that brings you onto the island!!!
Unique Suggestions: Go after you've been to Skellig or before you will go there to learn about the history and the nature of this place. But don't take it as a replacement!
Fun Alternatives: Go! If you can then get on a boat and go there!!! You won't regret it!