I am training for a 75 mile ride the first of April. I have been doing some intervals and 50 mile rides on Saturday. From March 13-18 I will be out of town and unable to ride. I am sure I can find some time to go running, but don't know if it will be of that much value.
How much fitness will I loose in a week?
I will have two weeks before the ride when I return home.
Thanks for your help.

You won't lose much.

First to go are the top-end, short-time power output. Aerobic engine you need for a mini-century shouldn't take much of a hit.

Running helps my riding much more than riding helps my running.

Just don't try that mid-season break and expect to either A. run fast, or B. ride fast. My legs were ALL catywompus after a week or so of running then trying to race track! No bueno!

M