Wes, Welcome to the site! The basic placement for the trans. mount will be close front to back, however the 2wd uses a rubber block that bolts to the tailshaft extension housing & on the 4x4 the extension is not used & a metal "adapter plate" is installed, it sits on rubber pads on the trans. crossmember. The problem is, you won't have any direct bolt-on way to get the trans. the right height off of the crossmember & attached since the bolt spacing between the Two is conciderably different. You would need to make some sort of [ shaped piece the correct height with holes on the bottom for the 4x4 trans. crossmember rubber pads & the top drilled to mount a regular TH350 mount...doable, Yes.
The driveshaft as you mentioned will need to be from a 2wd type slip yoke...depending on the height of the truck & the length of the trans. tailshaft...a 2wd shaft should/could be fairly close. Lorne