Full disclosure: My wife and I are in our mid 60's and walk from the SBR upper B bldg to Sunset beach (and back) at least twice during our two weeks. With that said:

The walk FROM Flamingo to Kim Sha Beach is MOSTLY all down hill...the walk back CAN involve a decent hill but if you cut along the water at SBR Villas there is no hill at all to Flamingo... just stairs down to water level and flat from there. <img src="http://www.traveltalkonline.com/forums/images/graemlins/toast.gif" alt="" />