2000 yards. When I swim alone, the LA Fitness option is a better choice. I am in and done quicker, plus I can stop and get something to eat if I want. I felt a good speed increase when my arm pull was something I concentrated on like a rythym. Here’s what I did, substituting more freestyle where the kicking should be.
Warmup Set (300y)
200 build by 50s @ 4:45, 2 x 50 @ 1:10
Main Set (1300y)
4 x [150 @ 3:50, 6 x 25 @ 0:40]
Warmdown Set (400y)
4 x [25 kick/50 swim/25 kick] @ 0:15 rest