The 5-day-a-week dilemma

I'm using Cool Running's half marathon training program right now, though I've modified it pretty heavily. At the moment I have no use for speedwork. I'm not actually training for a half (yet), this program works perfectly though for the 10-mile trail run I want to do in December.

My biggest dilemma is how many days to run. I've wanted to go up to 5, but I think I've decided that four days of running plus one day of cross training is more practical. Every training program I look at for distances longer than a 10K calls for 5 days running.

The problem lies here: I want Fridays and Sundays off completely, because I'm either doing my long run or racing Saturday. So, if I'm a 5-day-a-week runner, that means four of those days are consecutive.