My DS#2 is 10 weeks old today. I just went back through my training diary and I did my first ride at 3 weeks (for all of 20mins on the trainer). I had a minor labial tear with a few stitches (so nothing compared to your episiotomy). I was pretty nervous getting on for the first time and only planned to keep riding if there was absolutely no pain. I rode on the trainer so I could move around easily (and not have to worry about cars) and had a spare cloth nappy on standby to add a bit more padding if required. I was very conscious of slowing the healing by getting on the bike so for me I was well on the mend by 3wks.
Hear's my TMI advise. Don't go near the bike until you feel REALLY comfortable touching, moving, squeezing the scar tissue. If there is pain and sensitivity just to touch it you don't want to be sitting on a bike yet. In my non-medical opinion.
I'm also a big fan of the Concept 2 rowing machine, great cross training for running and cycling. Also good for abs and back strength which despite exercising through pg still seem to take a beating.
As others have said, time with baby and rest are very important but I understand your desire to get back on the bike. For me exercise has become my "me time" and break that allows me to recharge and then get back to the job of being a good parent. This is only possible though as my second one sleeps and feeds much better than #1 and I am getting lots more sleep/rest.

