I'm also gonna suggest doubles for you, they help a lot, but I wouldn't start them until you have a break from races, because they will make you very tired for a couple weeks. Also, when you do start them, you could do running doubles on the morning of workouts and then just bike the other mornings so that it isn't a ton of stress, but you're still getting good aerobic exercise. Good Luck!
Also, my training this week was the following:
M- am: 3 mi treadmill @ 9:00
pm: 4x800 CV (~6 min pace on icy roads) + 4x200 hard (~4:45 on same roads)
T- am: 3 mi treadmill @ 8:45
pm: 70 min easy @ 8:15 + 4 strides + weights (first time in about 9 months)
W- am: 3 mi treadmill @ 9:00
pm: 60 min easy @ 8:56 + 2 strides SORE
TH- am: 3 mi treadmill @ 9:00 + 5.5 mi/23 min bike
pm: 5 mi Tempo @ 6:30 +4x25 sec hard uphill + 2x10 sec sprints, felt amazing, wasn't too hard.
F- am: 3 mi treadmill @ 9:00 + 5.5 mi/23 min bike
pm: 45 min @ 8:35 + 4 strides
S- 120 min on treadmill @ 7:50 + 4 strides in hallway at 30, 60, 90 min.
SU- 30 min @ 8:17 + 2 strides
Total: 74 mi + 11 mi bike
Hoping to do well in the 16/32 for HS track this season and feel like I'm doing well so far. Last winter I was injured/sick till February so I'm way ahead and hoping I can cut some serious time off a 4:48 and actually run a serious 32.
Also, looks like your training is going good, have you tried rolling out your plantar facia on a hard corner (like a table)? It sounds gross but just use a wipe on the surface when you're done. It helped mine a while ago.
Good Luck!