Here's my idea..
M 4-5
T 5-6
W 4-5
T 5-6
F 4-5
S 5-6
S 6-8
So, aim for 4-6 during the week the 8 for a long run. Here is where it gets interesting...EVERY WEEK aim to increase one or more of those runs. Base it off the long run. If your long run is 8 then your weekly runs are no more than 6, if your long run is 10 then your weekly run are no more than 8..so by July or August you are running 8-10s with a long run of 12. Feel free to break up your mileage in doubles 2-3 days a week. In my day I would do 10 one day then 7/3 the next and just keep alternating then a 12-14 long run. On the double days my 7mi runs would be FAST for a portion.
As an example here are key weeks you should be building to..
M 4
T 6
W 4
T 6
W 4
T 6
F 4
S 6
S 8
M 4
T 5/3
W 6
T 5/3
W 6
T 5/3
F 6
S 6
S 10
M 6
T 6/4
W 8
T 6/4
F 8
S 8
S 12
M 5
T 7/3
W 10
T 7/3
F 10
S 10
S 14
Tues: warm up, run 2-4 mi hard, cooldown.
Thur: sprint 100-200m full recovery 200-400 jog, Repeat 5-10 times. Should not wear you out.
Alan