Any of them really. However, If you go with the 74 year, change the front sprocket back to a 17 if it has not been already. You may want to stay away from the 77/78 F bikes as their gearing is set a little more for accel unless you do not mind the slight additional buzzyness. The 78K is a very good touring bike. The seat is nice and it is very stable.
Remember, any answer you get will be purely opinion.
The ride IS the adventure. The destination is just to get gas!