If you ran 50 mpw last year and ran 15:50s then if you peak at 65 or so that should be good.
First, your body needs a break. Rest up. 3-4 days off. the rest of the week cross train 45 minutes max or go for a JOG for no more then 30 minutes.
Then progress mileage like this. (next week being #1.. #9 being 8/5 - 8/11)
1 20 Easy running
2 40
3 50
4 55
5 50 Recovery week
6 60
7 mid 60s
8 mid-high 60s
9 55 Recovery week
Weeks basic idea should be something like this..
Example of week 3
SUN- Rest or Cross Training 40-60 min
MON- Tempo 5k (5kpace + 0:30) or Fartlek (Ex: 1 min 5k - 1 min jog) X 15 (7 total)
TUE- Easy 3-4 am / Easy 7 pm
WED- Hills (20 sec x 15) (6-7 total)
THU- Easy 3-4 am / Easy 7 pm
FRI- Easy 6-7 + Striders
SAT- Long Run 9-10
@ 48-53 miles
Example of week 8
SUN- Rest or Cross Training 40-60 min or Easy 4-5 mi
MON- Easy 4 am / Easy 8 + Striders pm
TUE- Tempo 4-5 mi or Fartlek (Ex: 1-1,1-2.. 4-1,4-1.. 1-1 @ alt 5k/Easy) (8 Total)
WED- Same as monday
THU- Hills (250-300m x10) @ 5k effort (GOOD FORM) (7 Total)
FRI- Same as monday
SAT- Long Run 11-12
@ 62-68 miles
Take off at least 1 day every 3 weeks
Core/upper body exercises x3 per week
Lower body (lunges, air squats, jump squats, etc x2 per week)
Recovery weeks are weeks with just 1 Hill workout.. no tempo or fartlek .. replace with a easy 30-45 min run. Take time to recharge and be ready to go for the next week.
Remember for summer.. if your legs feel bad and you have tempo planned.. run it more like a progression run, start easy and end the mile or so at tempo pace or Dont push anything you cant handle. Be smart.
GOOD LUCK