If you are HS frosh/soph and not sub-51, I'd say run XC. It's only 5K. Just do it for the workouts; you need development and this is a great way to do it. Don't worry if your 5K times are in the 17-19 minute range; XC is all about preseason from your perspective.
Here's a generic summer/fall approach for HS 400/800 guys who are NOT running XC, and who are frosh/soph sub-51, or junior/senior sub-50:
5 days -
3-5 miles easy (depending on your previous mileage), pick up the pace to threshold effort for the last half-mile. 3-6 x 50-100m strides at mile effort, not faster, with good form as of running 600m. 4-12 x 50-100m drills.
1 day - warmup, 8-12 x 200m hills at 800m-1K effort, walk or jog down, 2-3 min recovery. Lunges (forward, side, diagonal), single-leg calf raises / heel drops, squat-jumps.
1 day off.
Do that all summer/fall to build strength and aerobic fitness. 4-6 weeks before track season, replace the weekly hill session with a track workout. 4 x 150m with 5 min rest. Smooth unforced accel on the curve, blast down the straightaway up on toes full speed with good form; try to sprint "fast relaxed" with good arms and upper body posture. Then jog 4-8 laps on the track, on the straights hop left-left-right-right or if that's too hard take 2 steps between left/right. It's light plyo work that builds leg strength.
This preseason plan should bring you into early track season with decent stamina, strength, and OK speed for that time of year.
Good luck, hope this helps.