You train on the track and get in one quality accel —-> speed endurance workout or accel—->max velocity workout per week. On top of that or another option is to warmup one of those days in the hallways put on your tights and go outside and run a special endurance rep. go back inside for the rest period and go back outside for the second rep. For example warmup inside go outside and run an all out 300 go back inside for 30 mins. go back outside run another 300. It would be difficult to get in a good max v. workout outdoors since you would need to be outside for an extended amount of time. For example 4×30 5×60. It would be a big pain in the ass to be going inside every few mins. plus the speed that those types of reps. would be done at may put the athleted at risk.
That takes care of 2 workouts. The other workout could be a combo of plyos, hurdle hop and lifting in addition to the 2 other days of lifting being done on the high intensity days.
Tempo could be done outside on the days in between or they may have acess to the pool. If not then the rower or treadmill be be a good option with general strength circuits and or sled dragging.