If you want to stick with metering the whole scene, you can use the exposure bias function to help prevent blow outs. Since the K-5 sensor lets you recover so much from shadows without excess noise I find this a good option for me. Shoot at -0.7 or -1.0 EV and you are all set. Of course you could also meter the sky and lock AE as previously suggested. Fixing in PP with these options is very easy.
I have a graduated ND8 rectangle filter, but rarely use it, as fixing in PP is easier than messing with a filter