You're not training poorly in relation to your goals, but I think there's def. a few things that you could improve upon:
1. Others have said it, and I'll add to the chorus: Double.
It's summer and it's hot out (well, unless your in the PNW or far up north). We trained in a hot climate back in college, and always factored in the extra wear and tear because of it when looking at our mileage totals AND structure. Going out and ripping all longer single runs is very likely going to beat the hell out of you. Throw in some doubles and you'll get the same benefit, recover better (so you can absorb the work and get faster more easily), and run less of a risk of digging your body into a hole.
2. Someone else said this, and I'd like to emphasize it: It's a LONG season. Regardless of what division your in, you're going to be competing until mid-late November. We wouldn't even consider "training" until the 1st of July (those of us that were older and more secure in our travel slots for the real meets). Everything before that is just making sure you're fit enough to start running with a purpose and recovered after a long year of hard work. You've got goals to meet and want to see large improvements, so obviously you're looking to do something extra to take you to a far greater level than if you'd just progressed normally - and that's fine. Just think about maybe hanging out in the 70 mpw range until the 2nd week of July and getting used to fitting in some strides/efficiency work and 1 progression/light tempo (as in 5-8 miles of work in the marathon pace +/- 10 seconds down to just touching date 10k pace) per week. After than ramp up and do 3 weeks building, 1 week "recovery" (so for you 70-80-90-75-90-95-100, etc. until you find a rhythm you like).
3. I touched on it above, but MAKE SURE YOU'RE NOT JUST JOGGING. Do strides after runs. Don't like it? Hammer between lightposts for the last mile of some runs. Throw in some as-you-feel progressions and work into planned ones as you progress through the summer. These will help you immensely when you get back to school.
4. Do NOT worry about pace. That goes for both easy and progression-type runs. As an example: I'd jog around between 7 and 8 minute pace most of the summer. Sometimes finishing a bit faster, but usually no better than 6:30 or so the last mile or two - that actually goes for once I got back to school, too, but we're not discussing that now. Progression runs? Yeah, I'd be stoked if I was getting my last couple miles under 5:20 when our coach was asking for them to be ending in the 5:00-10 range. DON'T WORRY. Have confidence that when you get back to school and are in a big group rolling along that the pace needed (which you may not have run all summer) will come easily and at the same RPE and HR that you were doing by yourself (or at least that's what my teammates and I found).
5. Once you get back to school, try to not care about too many races. I know that sounds weird, but just...get used to racing and don't sacrifice your training for pointless early season meets. Sure, my team would travel a full squad to 8-9 meets per year (that's including conference, regionals, and nationals). However, those of us secure in our slots and not racing to make the top 7-10 would be under orders to do nothing more than run the first 3-4 miles at LT pace and then pop down the last bit to 8k pace OR see how fast we could finish/race. In reality, we raced hard at 3-4 races all year (including conference and NCAA's (we had a weak region and could all but call it in)). My point, having dragged down memory lane a bit, is that you need to focus on keeping your training cycle rolling and not interrupting it just so you can sling a big dick against some randoms at a meet nobody will care about in 2 weeks. Keep it in your shorts until the big at large points gathering meets and the championship season.
Ah....I think that's it? Sorry that got a bit long, but I wanted to lay out what I've seen be the most successful for the largest amount of people (so not JUST myself). Feel free to ask questions.
Source: 16:10, 9:48 HS athlete who improved enough doing that to have NCAA XC and T&F trophies.