Hi Diann - Congratulations on finishing STS! That's a great accomplishment!
Cathe publishes monthly rotations that typically use a variety of dvds from all her series. They can be found on the forums, her blog, and in the Workout Manager. She also has rotations in the User Guides for each series (at least the newer ones). Some of her rotations are longer, either 2 or 3 months (STS is the longest).
Depending on what you own or what your fitness goals are, you can find a number of rotations to meet your goals. Cathe's rotations are usually 6 days/week so you will need to modify them by substituting your weekend mountain biking for one of the cardio days, and changing around the days to suit your schedule. Have fun!