Stuck in 1st gear

Driving home yesterday as I went to pass a slow moving truck I went for 2nd gear and nothing, coasted to the side of the road. Put it in 2nd and car would not budge, no 3rd or 4th, only 1st. Drove home (about 5 miles) in 1st ugh. When I got home I had reverse and first, parked it to cool off.
Later went out to put the car on the lift and the shifter would not come out of 1st. Disconnected the linkage and the shift lever still won’t come out of 1st, definitely something internal. I know the trans has to come out but my question is, is it worth it or even possible to remove the side cover with the trans still in the car(67 A body)? I’m not sure there’s enough room to remove it with the shift forks and all. BTW this is my first manual car in a while, I’ve done plenty of auto,s just not familiar with all the tricks for a manual.
Looking forward to any advice