Workout

Warm-up (500)
300 swim, 100 kick 
100 drill

Set (400)
8 x 50 build on 1:00

Set (1500)
2 rounds
100 IM on 2:00
2 x 75 on 2:00 
...stroke/free/stroke by 25  
4 x 50  on 1:30
...stroke/easy free by 25
8 x 25 FAST on :1:00
100 easy on 2:20

Set (400)
2 x 200 pull
...5/3cb by 50

Cool-down (200)
200 EZ choice