Need help with a routine

Anyone out there in dire need of  a project. 

Here I am 

I am 5"6, and weighing 124. I generally go for 45 minutes rides, 10 minutes jog at 13 minute mile, and I am quite active during the day.

I have a significant amount of muscle on my legs and thighs due to bike riding, I would absolutely love to slim them down and make them leaner...

I have found this wonderful website 

What I am really looking for is some hints as to how many reps I should be doing, and how many times I should do weights.

Well... if it's all muscle on your thighs you might try doing body or light weight exercises for your lower body (squats, lunges, step-ups, jump squats, jump lunges, etc.) Go for 20-25 reps per set, and do 3 or 4 sets.

If by "slim down" you mean that you need to lose fat covering the muscle, high intensity interval cardio is the way to go, along with lifting moderate weights in the 8-12 rep range.