These are not necessarily on the CT or CDT.
Elk Park-Needleton loop around Chicago Basin. Options to climb 14ers.
Four-Pass Loop. Options to climb 13ers and 14ers assuming a higher skill level for some.
Cross Creek-Fall Creek loop in the Holy Cross Wilderness. Option to climb Mt. of the Holy Cross.
A Collegiate Peaks Wilderness loop or out and back or car shuttle including options to climb Missourri, Belford, Oxford, Harvard, Huron, Columbia and Yale along with high 13ers like Emerald and Iowa. Utilizing CDT, Pine Creek Trail, Missouri TH, and CT any combination of them or all of them.
There are more trips is you exclude 14ers, the longest trips can be put together in the San Juans and then in the Collegiate Peaks if you get creative. For CDT or CT trips the San Juans provide the most and best options then the Collegiates.
Let me know if you need any details on these.