Ugh, the hill up to Bulla - I walked it last time I was there. Turning left on Feehans Road just before Sunbury and then hooking up with Wildwood Road looks like a good alternative. You bypass Sunbury and Bulla and, though you still have to deal with the same valley, it’s a bit mellower on Wildwood and there’s no cars. (also no BP at the top - sorry nick!)
once, however, this random guy in tight black jeans on an old steel roadie with a can of melbourne bitter in his bottle cage jumped on the back of ten of us roadies and held on all the way up the other side.