It's the Spring of the Summer of Malmo threads!
Based on your times, your mile time is by far the strongest - a 5:12 mile is worth about 11 minutes for two miles and mid/high 17s for 5k cross country. This could be because you're truly a miler, or as is commonly true for younger athletes, your aerobic system is underdeveloped. So if your goal is to race well in cross and mile/2 mile track, summer should mostly be about patiently and consistently developing your aerobic capacity.
What does this mean in the SoM?
1. Run more. You didn't mention your mileage, but pretty much no matter what it is, you'll benefit from increasing it. But the majority of that running should be *easy*, like, probably easier than you run in-season. Don't worry about pace/heart rate/etc. - easy is an effort level, not a pace. Malmo says don't stress a weekly long run. Increase mileage as you feel able - it might come quicker than you expect if you keep it *easy*.
2. Do some faster running, but do it *easier* than you think you should. Build your tempo towards 4 miles, but start slower than you think you need to. If you end up cutting down the pace in the last few miles, fine, but no going all out. You mention feeling like you "could probably go faster" on tempo runs - don't! The point of tempos is not to go as fast as possible - it's to get your body and mind used to going decently quick for a fairly long period of time, but finishing with plenty more in the tank. Some 200s are great, but don't worry about time on those either, and take plenty of jog recovery between each one. It can feel fast during the rep, but if you're doing, e.g., 10x200, it shouldn't feel *cumulatively* hard - that is, no hobbling through the cooldown and needing a day off after. Smooth, easy turnover to get you ready for fall workouts is all.
3. Don't overthink it. If you're planning a tempo and feel like crap, do an easy jog instead, and do the tempo the next day. If you feel great on a run, push the last few miles and call that your tempo for the week. If you miss a few days, don't worry. No one day in the summer will make or break your season, so that means no hero workouts, but also no pushing through a little twinge, or beating yourself up for missing a day on vacation. Patient, consistent, and hit the fall ready to train hard, not burnt out.
Happy running!