Just some feedback from what I looked at:
1) I agree that spinning with a high cadence is good. 90-100 is good. Get a bike computer to know what your cadence is. But on pg. 7 it states "You will probably bounce in your saddle while spinning. That's OK." No, it's not OK. There comes a point where you are giving away some of your power. To pedal like that the entire time you ride is not a good idea.
2) Since you are already riding some, I think you can do more distance on your bike days. Honestly, rides in the 15-20 mile range would NOT hurt you. If you think you might be weak on the run, train more for the bike portion. That way, you come off the 12 mile ride fresh.
3) Since you are already swimming, I would just combine the two days of swimming into one workout. You can get through a sprint only training one day a week in the pool. That way, you can cut your days from 5-6 to 4-5.
4) Like it was stated before, it's OK to lose the weights. Unless you already do them and feel comfortable leaving that portion in the training program.
5) Honestly, training 4 days a week for a sprint is enough. No need to train 5-6 days a week. It's overkill.
6) Since you have injuries associated with running, you might want to look at only doing 2 sessions a week. Now, that can be a stand alone run session and a brick.
That's my feedback. Please keep in mind though, I have a coach who tells me what to do. And I've been doing that for 2 of my 4 years of tri training.
Good luck and have fun! Get your rest and don't kill yourself training for this!
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"