I have done both doors. I would recommend getting a rebuild kit from Classic industries. Comes with spring, Bushings and pin. You will need help or you can use and engine hoist to hold up the door. You will need to cut or grind the bottom of the pin and drive it out. Use lots of lubricant and once you have the first pin out you can use it to drive the others out. HB sells a spring tool for under 10 bucks that will help in installing the new spring. Hope this helps
Get a spring compresser to remove door spring and some times the hinge pins are tough to remove because it is hard to get a good swing with a hammer to drive pin up and out.I used a impact gun to drive my pins out and then finished them up with vise grips to wiggle them out the rest of the way.I remove my doors by myself all the time by holding the door with one hand and removing top pin with the other hand just be careful not to hit the fender while removing door
Before I sold my 74, I replaced the doors with ones from a 73 (original ones were rotted out). It was a huge pain to do, took a lot of hammer slamming and penetrating oil to finally get it out. I also heated it up with a propane torch , which helped a little.