Tom, thanks for your help. I am understanding that I would just leave the horizontal run of pipe into the 14"x14" hole and that would leave me enough room for the rest of the plumbing, correct?

Correctomundo, First position and set the trap. I can give you approximant figures. The center of the trap inlet should be 1 1/2" in from the front wall line, (bottom plate) and 15 1/2" out from the side wall, Set the tub, (Don't forget the 2X4 uprights on the wall to hold it steady) and then install the tub waste and overflow. Last position the tub shoe and drain to see if you will have to cut some off the "tail" of the tub shoe and run a ring of plumbers putty around the drain and screw the chrome drain in the tub shoe. Lastly, install the strainer. You have just installed the drainage for your tub. Good luck, Tom