Which hills that are miles long are you talking about? The Tomales/Bodega road over the peninsula? Mt Veeder? Pope Valley? Ink Grade?
Tom is correct about the gearing, so you want to look at the grades you'd be doing on club rides. Will the shop let you test ride up a good grade to see which one you like?
Most of the members of my club that have been riding for years and are eligible for AARP are riding triples, even the ones that still hit the gym regularly and also run.