Just note that if you train hard, rest hard. If you are going hard it twice a week for 25mi (40k), as a newer rider you may have to go easy every couple of weeks and start with the B group, dare I say it. As you get more "base milege" (just getting miles in at a moderate, easy pace) your body will adapt to the effects of training and be more able to recovery and adapt, therefore increasing performance over time.

I hope this made sense?