A little training advice

Hello all I am planning on swimming the width of Lake Tahoe (10.5 miles), in September, 2018. I was wondering if some of the coaches, or senior members, or any one for that matter, has some suggestions on workouts for the pool (i.e. 12 week program TI style. Been doing TI for over ten years but mostly trained in open water, that part is easy for me. Please feel free to offer up some advice. I swim in a 33.3 yard pool and my stroke count is 20 strokes per lap. Thank you again for your help!

Keep Swimming!
Naji