Phang Nga Bay and Railay Beach

[watgate]

We would like to take a tour of Phang Nga Bay as well as take a tour of the Railay Beach area. I have never been to this part of Thailand so was wondering is their a suggested location to take in both sights or should we stay in 2 different areas to be closer to each area we would like to see? I realize Phang Nga Bay is quite expansive so would probably take a tour to see James Bond island and what ever else is typically included in the tour of the bay. We are interested in seeing how this Bay compares to Halong Bay in Vietnam. As for the Railay Beach area the scenery sounds great so we would like to take a boat tour of this area as well. My big question is are both places we want to see doable from one centrally located hotel or would it be better to maybe stay 2 nites in the Krabi area to see Phang Nga Bay and 2 nites in Ao Nang to see the Railay Beach area? Any info would be most appreciated to help me plan the trip.