Don't forget that not all hills are equal. If they're 2-5% grade, that's one thing, but if they're 6-10%, that's another when it comes to the time needed to climb them.

If you have the time, you might run down a copy of Performance Cycling by Stuart Baird. He uses some math and scientific principles to explain a lot about what happens when cycling, and although it is geared towards racing, the principles are the same. He has a section called "Nonuniform Conditions" where he talks about the effects of wind and hills and what strategies are best when encountering them. Although it sounds kind of geeky, it's actually written pretty well and easy to understand. I have recommended the book to others and they liked it.