I've found during the summer
1. best to do the important stuff in the morning, because of the heat (if you live somewhere that this isn't an issue, then I guess you can do the hard stuff in the afternoon if you like)
2. You don't need to do a ton of sprinting for it to be effective. I'm heading out to my team's workout in about 30 min and this is what we're going to do.: Short run followed by drills and wickets, followed by some short (60m) sprints on the track, followed by weights.
3. Weights are not for building muscle. You're trying to build structural integrity in your musculoskeletal system. Keep the sets and reps low and the loads comfortably high (85% ish of max). We're only going 2 x 5 on each lift. You want big, compound lifts, preferably with free weights. We're going to use 1 push, 1 pull, 1 squat, 1 hinge, and a number of different core stability exercises. What we're going to do today: Bench Press, Pull Up, Split Squat, Dead Lift + some of Jay Johnson's SAM stuff.