A entry door is 1 3/4" thick so you would need a supplier that you could get 8/4 lumber from. The stiles need to be especially straight so you either need buy enough lumber to get a couple of straight boards or have the equipment to flatten the stiles before surfacing them. The finished stile is usually 7" wide so you would need a 8" jointer or wider to face them. It just takes less lumber if you get the wood rough and mill the stiles flat first before surfacing. The panels are usually 1 3/8" thick with a raise on both sides. Unless you use multiple panels the wood would need to be glued up for the raised panels. Since it is a exterior door subject to the weather you would need to use an exterior glue such as titebond III. The only real difference the coping and sticking set for a entry door is profile on both sides. Unlike the cabinet door though which is ready to assemble after milling the parts the entry door needs dowels too to keep it together. I normally use 2- 1/2" dowels 5" long in each joint with the exception of the bottom rail which I use 4 dowels.
You could cut the wood with the bandsaw and work it flat with a hand plane. It would just be too much work for me. If you are experienced with mortise and tennons then I would prefer that. Most folks would use dowels because it is easier. You wouldn't necessarily need a 5" tenon on your rails. The 5" length for the dowels was 2 1/2" into each part.
