Up here (in winter land) my arse is always sore after my first longer ride in the spring. Even after a couple months off the bike, it takes some adjustment.
Also, when I am speeding downhill or riding too fast through traffic, I move my hands down on the drops to be ready to brake more quickly- in the drops you can pull lower down on the levers where it's easier to pull them harder.
Anyway, sounds like you're on the right path. Keep riding and have a good time.