[UPDATE]
I replaced the clutch hydraulics (Master and Slave cylinder and connecting pipe) last weekend and my inability to shift to 1st and Reverse gear has been solved. I would like to all the folks here on this thread that wrote back to my original post. Some wrote long messages detailing test procedures (Gary Croyle: that would be you). Thank You to all.
To all the folks on this thread that wrote back: People like you give people like me the courage, knowledge and ideas to try to new things and become better DIYers. As a believer of karma, may you all get back good karma.
I have to also thank Andy Hacker of City Diesel in Knoxville who took the time to test drive the truck, lie down in the parking lot, etc. to see what the issue was. Eventually, he suggested replacement of clutch hydraulics. The clutch kit (flywheel, clutch plate, pressure plate, pilot and release bearing work was done by another shop). I don't think I would trust anyone other than City Diesel in Knoxville for future work that I am unable to do.
It appears that I also solved the vibration issue. I found that the center support bearing bracket was remounted at a slight angle, in addition to being pushed towards the back of the truck by a bit. I was able to see this from the old "rust marks". I loosened it and aligned it back to the old "rust marks" and the vibration appears to have gone away.
Once again, THANK YOU.
Attention: TDR Forum Junkies 
