Workout

Warm-Up (300)
300 swim

Set (1000)
5 x 200 
...odds free, evens 50 kick/50 swim
...w/15 sec rest

Main Set (1800) 
...fast all free, easy optional to add back

3 x 100 fast on 1:45
3 x 100 easy on 2:00
3 x 50 fast on 1:00
3 x 50 easy on 1:15
3 x 100 easy on 2:00
3 x 100 fast on 1:45
3 x 50 easy on 1:15
3 x 50 fast on 1:00

Cool-down
100 easy