I am getting ready to ride a very hilly...
I am getting ready to ride a very hilly century ride in northern Georgia called "the Six Gap". It has 11,000 feet of climb, just climbing over the six gaps, and doesn't count the mountains in between, which I am told adds another 6,000 feet of climbing.
I am riding a Sram Red compact, Dura Ace derailers(no spellcheck), and a Sram 12/28 cassette. Can I use a larger cassette like 12/30 with the components I have
yes, you shouldn't have a problem with going up to 30 tooth in the rear cassette with a Dura-Ace RD. With a compact crank you will have to be heading up some serious slope to really need it, unless you ride with Contador-style cadence on the climbs.