Warmup 300 swim 200 kick 100 pull 300 swim 200 pull 100 kick 6 x 50 (drill 25, swim 25); odd free, even stroke on 10-15 sec rest interval

Main set:
3 times through the following:

150 (all free)
150 (50 free / 50 stroke / 50 free)
150 (50 stroke / 50 free / 50 stroke)
150 (all stroke)

200 kick

Free is easy to moderate effort; stroke is fast

Pick an interval that gives 20-30 sec rest for the all free 150, then add 5 sec to that interval for each following 150

200 easy

4100 yards/meters