500 SCY Attempt to make state cut.

Long story short I graduated high school last year and never swam but junior and senior year I considered it but decided against it. Now I want to show myself that I could have made a state cut. Background: Traditionally a runner. PB of 19:35 for 3 miles Do ~20 miles a week One attempt at 400 LCM free from a push off was 8:20 (beginning of a triathlon) Before that attempt I was doing workouts of 100 w/u 4x100 free 1:45-1:50 on 2:15 interval 100 easy 4x100 free 1:45-1:50 on 2:15 interval 200 warm down on an irregular basis of about 1-2 times per week Goal: Intermediate goal: 7:15 SCY So the question: Recommended workout in this situation. Assuming that I will consistently be going to the pool 3-5 times a week. Thanks for the help!