How should i structure..

Yenzehc

Hello everyone. I'd like some advice of the structure of my running plan.

Currently following the C210k program

Just reached week 9 or a total of running for 30mins at a time ( No rest)

My issue is when i can run, my work does not allow for the simple, monday, weds and friday plan.

Well.. it does for 1 week at a time. Then its 5 days off.

Example;

Week 1 : Mon,wed,friday
Week 2 :can't run
Week 3: Mon, wed, friday

How do i retain my current fitness level by only working out everyother week ?

Bare in mind i am supplementing the week off running with 15 mile rides every day for 4 days of work