www.bikely.com is another good bike route site and gives good elevation maps. I completely empathize with the OP as I have issues with hills too, being about 30lbs over weight. I've done flat centuries, but I'm intimidated by hills. My goal for this season is to complete a hilly century going from Boston on Rt62 out
to Barre and back, its about 110 miles and will have 7000' of climbing. It's part of the BMB route and it freaks me out that on that ride they go from Boston to Barre in about 4 hours.
My approach is to work up to the whole thing by doing sections each weekend. I'll start by doing Boston to Sterling and back, the next week I'll try the hilly bit Sterling-Barre-Sterling. Hopefully I'll do the whole ride on one very long day sometime this summer.