Although leaving the mounts in is probably the easiest, I had to removed mine as they needed to be replaced. I ended up removing the pinion shaft to access the nut. Getting the nuts back on is tons of fun as well. Not much room for fingers or wrenches, but patience prevails. Make sure to get the alignment tool (Moss# 453-622) if you have a '77, as you will need to make sure the pinion shaft is properly aligned before you put it back together (not sure this is necessary if you just remove/reinstall, but I replaced the rack, and it definitely needs to be aligned if you loosen/remove the rack from its mounts.)
Good luck!