Are you getting up early enough? You need to have time to eat, get dressed, have body wake up a bit and then ride. I'd ride the first part at low cadence and low power, just getting the joints working. Don't push it up the hill, spin, spin, spin, but take your time. Another alternative is to add an extra mile to your route before you hit the hill, by then everything should be flowing and the hill should be a tad easier. Remember it takes time to get the muscles back in work shape.