Unkilrod, Jumping out of gear for first gear will probably be:
1)Interlock/detent/shifter fork on side cover worn
2)uneven wear on teeth of cluster gear or 1-R slider gear
for 2&3:
1)Interlock/detent/fork/ring on OD of syncrothat fork engages
2)uneven wear on the engaging splines of the effected end of the syncronizer or gear it mates with (main drive or 2nd)-usually these situations jump out when pulling.
less likely is problem w/pilot bearing in end of c/s
just my 2 cents worth
