I agree with Dom. My advice is to meet in the middle.
If possible, travel at night because it's much less stressful for the iguana... s/he will sleep through the entire trip.
You can use a large pet crate, put a blanket in the bottom. Hot water bottles work; however, you'll need to fill them when you get the iguana.
A better way to go is to buy a power inverter from Radio Shack (or other store, about $50). This will plug into a power port or lighter and you can plug a human heating pad into it. put the heating pad on LOW under the blanket.
You should also bring an extra blanket to put OVER the crate to help keep any passing light out and the warmth in.
I've transported iguanas this way, and it is the way to go.

Best wishes, and do keep us posted.