I'm planning an 8-day trip to Dublin in early - mid-October, and I'd like to know if my itinerary sounds realistic. 

My trips outside of Dublin would be to Counties Wicklow and Meath, where I'd like to see: Glendalough, take a hike in the Wicklow Mountains, Powerscourt, the Bru na Boinne, Newgrange, Knowth, Trim Castle, Loughcrew Cairns, and Dalkey Island (if possible).

Do you think this is realistic for 8 days?

Also, I know I don't need a car to get around Dublin, and that public transport goes to many of the places in Counties Meath and Wicklow that I've mentioned.  Still, would it make more sense to rent a car than rely on public transport to get to my non-Dublin destinations?

(This will be my fourth trip to Ireland! )

Thanks so much,

Dan