First issue is "normal" to a point. If your driveline is bound up at all, you will not be able to move the little shifting collar. It is suggested in the owners manual to try and back up a few feet, while trying to shift the t-case from 4WD.
The second issue:
There is not a syncro on the reverse gear in your transmission. Your linkage rod on the slave cylinder could need to be lengthend a little, there is a threaded adjustment on this piece. When you see it, you will understand. Perhaps the clutch is not releasing completly when you depress the pedal. Another thing you could do, is just put the truck into second gear, and then into reverse, therby using the second gear syncro to slow the rotating gears in the trans. I would adjust the linkage first tho..
Good luck!
-Steve