We have two full size folding cots from Cabela's and they fit great with plenty of space each side in a T4, if we offset them so they are side by side with about a foot or so from one wall, we have room for a 24"X36" fabric dog crate on the opposite side of the tent. One thing to remember is the tent has much lower headroom at the exterior wall, with the cot centered I can not stand up straight along side my cot, but the way the 4 sides pop out, there is a lot of elbow room to get dressed even if stooped a bit. the dog crate side has plenty of room. If you have cots spread apart they kind of block the doors, but there is just enough room to squeeze by on one end, and the free center space gives lots of room to stand fully, also you can use a small table and sit on the cots for a game of cards or dinner if the weather is really crappy outside. Overall we love the tent, well worth putting up with the extra weight and long transport length to be able to have a large dry space that sets up fast.