You are going to want to run some flex duct (preferably insulated ducting for noise and keeping the heat inside the duct line and not radiating back into the tent or room) off of the 4" fan and out a window. You can let it dump the exhaust into the room that the tent is in, ONLY if you are drawing in fresh air from outside. If you are doing a passive intake, or fan blowing air in from the same room, then you are only going to be able to get the growing area as cool as the ambient temperature in the house/room.
Everything else looks solid, just remember that you need a complete air exchange across the tent. Considering that you do not have a carbon filter masking the smell, you should think about bringing air from a window or HVAC vent, so that the air that is coming in is cooler and is fresh air that is not being exhausted and recirculated. Check out these guys and how they explain how to set up a grow tent.
http://www.youtube.com/watch?v=VS5eyx_oEzw