Might I suggest you look into some basic gentle stretching routines. Your quads will adapt in time but the stretching will help stop you tightening up and prevent stress injuries. Nothing too severe - just 15/20 mins per day.I'm into day 3 of my first attempt at a full week commuting.
It's not going too bad, and luckily the weather has been kind. I basically just getting out of bed, quick drink of water, brush my teeth and then straight on the bike. Shower and breakfast when I get to work, then I'm good to go.
It's been hard on my legs doing back to back rides, not in terms of the distance (10km each way with a hill at either end), but 2 rides in a day and consecutive days. My quads are certainly feeling a bit heavy this morning. Hopefully, I can see out the week before my legs give in and then have a good rest over the weekend, then see how next week goes.