Your system could just need to be bled, though if does could mean the master or slave cylinder is on the way out.
Look for simple solutions first.
I usually have to slip the clutch a bit to get mine to go into reverse, going to try 2nd to reverse the next time. Thx Flyer58!
Didn't know about the 5th to R lock-out either, but it makes sense.
Shortly after I bought mine, storage mortality reared it's ugly head in the clutch, brake and fuel systems.
Unbeknownst to me, it had been parked for about 10 years, probably more.