Also buy a side tent for the dog. We use this one http://tinyurl.com/qa5k8 You can see it on our tear in our Album, it's nice to be able to get dressed standing up and also have a place for the portapotty. We have a vent fan but really haven't used it that much, we do like having the vent open when sleeping but seldom turn on the fan. But for the few times we have used the fan (we have a northern breeze) it was worth having it there to draw out the hot air.
Two doors is essential or you'll be crawling over each other and there really isn't enough room for that. And windows that open on either side is also a must.
If you are looking on saving money, skimp on the inside cabinets or galley, not the sleeping area. You can always add to the galley or put in more cabinets but you can't make a 4x8 tear any bigger than 4x8.
Get some cardboard and build a mock up tear in the back yard or garage to see how big it would be, then you can make a better informed decision. Even if you're having someone else build it, by mocking up the size you can see the difference in sizes for yourself.
Good luck!
Juli n Bill
