When I built my Hawk in 2012, I put a fantastic fan over the kitchen area and a fantastic "vent" over the bed area. A fan over the kitchen just makes sense if you do any cooking inside. A vent or fan over the bed in a hot climate makes good sense to me as well...also gives you a skylight, even though its a small one. You have the option to upgrade to a fan at a later date should you choose to. At the time, I wasn't sure about having a fan over the bed. Within a year of camping in my Hawk, I decided to replace the vent with a fan. The wires were already there (thanks FWC) and the install was easy, even for me. My fantastic fans (there are 3 models I think) have 3 speeds, a switch for intake or exhaust and they are a nice option. Low speed is fairly quiet, but on speed 2 and 3 and you will know the fan is on. The noise is worth the benefits of having good air flow.
So, my 2cents, get a fantastic fan over the kitchen. If unsure about the bed area, at least get a vent put in (easier now than later) and be sure it's pre-wired for a fan.
Happy trails...