former club swimmer, looking to get back into form for tryouts

Hi everyone,

I'm a high school swimmer (male) who did club for about ten years and high school swimming, (so swimming has been a large part of my life), but I've always been about average (i.e. 50 free yards ~26, 100 free yards ~59).

This past year I took time off from swimming to focus on my academics, and I'd like to retryout for my local club team. The tryout is just a single set (5 x 100s free on 1:20, 3 mins rest, 3 x 100s IM on 1:40, 3 mins rest, 3 x 100s kick on 2:10). However, I'm definitely out of shape, and I've been back in the pool for only about two weeks.

While I can do the second and third parts easily, the first part is killing me right now, and I can only hold about a 1:30. Any tips/sets to get my freestyle endurance up at a higher pace?

Thanks!