I run 4km's (2.5miles) Monday, Wednesday, Friday and 2.4km's (1.5miles) Tuesday, Thursday, Sunday.
When I get my 4km time down to 17mins I'm going to move up to 5kms. I run the 2.4km because it is one of the BFA's in the army. I also do a beep test (20m intervals, running back and forth keeping up with a series of beeps on a CD) on saturdays. I also lift on Mon,Tues,Thurs,Friday.
As long as your eating right you can tone up while running everyday, be sure to keep your lifting (if you are lifting) atleast 8hours apart from your running e.g : I lift at 11am and run at 8pm, or if your not as lazy as me get up early (6am-7am) and lift
late afternoon.
Just my 2cents.