If the bottom bolts holding the core are half rusted away, it would be easier off the machine. If the core is completely messed up you could take it apart like a copper thief, i.e. saw across the top & bottom of the core to remove the major chunk and main impediment to easy bolt access.
Remove it as a unit works best for me. Then lay the radiator on a table that way you can get to bolts easier JM
As G Pete said, some of the lower tank bolts may be partly rusted away. I had that situation on my TWENTY tank and had to get a new pair of vice-grips and use heat to get them out. You need the radiator off and a table as "skinner" suggests to do that.
JanM