'83 B2000 Lost Reverse

I picked up a '83 B2000 about 80 miles from my home last week. When I test drove all gears worked. I ran a few errands close to where I bought the truck and all gears worked; in and out of parking lots, etc. I hit the highway and drove about 70 miles straight. Once I got to the house I went to back into the drive and reverse is gone. I cannot even find the gate to get into gear, there is nothing to the right or below fifth, like I'm hitting a wall.

I've tried getting into reverse from every position I can think of; truck running, truck off, rolling forward, rolling in reverse, from every other gear position, etc.
I've pulled the linkage and as much as I can see it all looks clean.
I pulled the reverse light switch with no luck (I saw a lot of comments that the switch has gotten in the way for others).
I added a spacer between the clutch slave and linkage on the side of the transmission to get more throw out of the clutch.

Any other ideas or suggestions would be appreciated. I really don't want to rebuild the tranny after only owning it for a week. Thank you.

Oil level good? Have you tried getting into reverse with the truck rolling very slowly in either direction? Is the shifter sloppy when in gear (indicating bad shifter bushings)

Oil level is good. Tried rolling fast and slow, forward and reverse with no luck. Shifter is a little sloppy.

I've taken the shifter off the top of the tranny and the bushings look good. With the shifter off I can get the tranny through all six gears with no issue.

Even though the bushings look good the only thing I can think to do is go ahead and replace them. Now...where do I get them? I've Googled for hours and can't find a set out there. Does anyone know a good supplier of parts for these trucks?

See if the reverse switch is "frozen". You should feel a resistance and "spring" actcion... You can test it by removing the switch and see if the gear shift goes into the reverse slot.

Get your bushings at the dealership - they are not that expensive... I didn't same a couple winters ago on my automatic - amazing how much better ti shifts.