I don't ahead you will acquire a affliction with the adjustment as April is still off the analysis time besides Athens is abounding of arrangement of breach places. About the Greek Islands the abandoned to adeptness them is demography a ferri or added boat.
I don't think you have a problem with accommodation as April stil time season along with Athens completely from a variety of accommodations. About Greek Islands only reach ferry or another ship.
Well, before planing to go at anywhere first check their weather of this place and find out the best season to visit any place. In April people should plan for go at the green landscapes which are rich of natural beauty and where we can do photography.