You will likely be required to check in on Friday, so you will need a hotel Fri, Sat, and Sun night. Assuming you dont planning on traveling the night you finish.

For my IMs with a Sunday race, I book Thurs-Sun, checking out Monday. My first IM, Canada in 2001, I had a flight in the early AM day after. Stunningly bad idea. Get there a bit early, check out the course a bit, give your self enough time to get everything set up the way you want it, have some good food, good sleep. Book a late afternoon flight out on Monday, and enjoy the feeling of waht you've just accomplished as you lay in bed Monday morning...