2100 yards - nice mixture

(done in a 40 yard pool but can easily be modified)

200 swim
200 kick
200 pull

8x40 free on :45
8x40 back on :50

40 ez

2 x (100 on 1:50, 100 on 1:40, 100 on 1:30)

8 x 20 sprint (alternate free and fly) on :30

60 ez