Czchman -
I bolted the front 2x4 to the door hinges because the door hinges are very convenient to reach and they are not UNDER the cab. If you bolt the front 2x4 to the front cab mounts, you will need to jack up the font of the cab and slide the 2x4 between the cab and frame. This is not necessary when using the door hinges. Also, when it's time to re-install the cab, using the door hinges makes it is easy to position the cab over the front cab mounts and drop the bolts in place.
