Joeybear, personally, I choose Tuesday, Thursday, and Saturday on purpose because I know most 5Ks are on Saturdays and they will take the place of my normal run. However, If that is how you have to do it, then do it. I think you would be best spacing them out, but running them three days in a row is better than not at all. I think when the next week comes you will find that the four days off might be too much, especially starting out. I think you will be hurting after the first few workouts at least and doing another run the next day will be tough.