[MidOHasp]

Have you tried float-shifting it? (i.e. - without touching the clutch, gently pull out of gear as you roll off the throttle and gently coax into the next higher gear as your revs fall. As the revs hit the synchro point, it should nicely (and without any drama) slide into gear...)

If that works, sounds like your tranny (synchros) is probably doing alright, and I'd focus on the clutch.

Hydraulic clutch? may need bled... Throwout bearing may need re-adjustment...

Just my $.02