I always find that I can't really build mileage AND add quality work at the same time.  In this case, I would want to be adding mileage a lot more than I would want to be doing any kind of speed workout, with the thought that endurance would give me the biggest bang for my buck.  Then there's also the issue that building to a particular amount of miles per week isn't the same as being able to hold that volume week after week.  With so many missed weeks over the summer, it might make sense to throw a cutback or two in there as well.  It won't be the same volume, but you KNOW you can complete the distance, so anything you do between now and then will just be a bonus.

 

My guess is that you want the structure of a plan to follow, though?

I am no expert but for where you are, I tend to agree with this. It seems focusing on just increasing your weekly mileage volume might bring more benefits than adding short/fast workouts. Maybe something closer to the Higdon Novice 2? That one still does not have very high mileage, but you could probably lengthen each of the midweek runs a bit, or add a day (it is a 4 day/wk plan). The only speed sessions included are race pace workouts, but maybe this is enough for now.