I'm in a three-week stretch of hard training before a two week taper leading up to my 1/2-Ironman on August 4. This week:
M - 55 minute swim
T - hour-long bike workout (finally feeling very good in one of the gears for blend of power/speed)
W - three-hour bike workout
Th - 8 mile run this morning (with some 'hills' ...working some loops of expressway overpasses, pushing the pace both up and down)
Yesterday's ride was great. I worked different gears on each loop of an 8 mile circle of a forest preserve paved trail (Busse Woods). My stamina at the end was as strong as the start. In the past, I've tended to slip as I got around 2 hours, but I was still strong toward the end of 3 hours (and this equates to my upcoming bike leg ..time and distance). Very encouraging!
I'm trying to keep my runs to twice a week (and about 20 miles/week) due to the sore Achilles tendon.
I'm hoping to take Friday afternoon off and head to the Chicago lakefront with my wetsuit for some swimming in Lake Michigan.
Stretching: I try to mix in stretching/flexibility throughout the week, and therefore don't do much before or after specific workouts (time constraints enter in as well). I know I loosen up after about a mile of running (or, as recently noted, when biking before a run). I'm the old guy here and can get by without much stretching.

I think we each need to know our own situation and deal with it accordingly.