Replacing the positive cable was a PITA on my 1980. I worked from the battery forward and had the car on jackstands. This did not leave much room to move, and a lift would be the way to go. Working around the drive shaft limits the space available and I found the "ratchet" type wrenches useful in several spots.
Just be careful with the route and clearances of the positive cable as you don't want the cable to wear on the propeller (drive) shaft.
I run my down the center of the car inside under the consel. I don't know if that is a saftey hazzard or not but it was easy and the cable is prtected from the elements. I drilled a hole, used a rubber grommet and run it through the wall behind the seat under the armrest, through the consel and another hole in the firewall with another rubber grommet.
Had it this way for 14 years without a problem.