Changing the radiator out isn't that hard, it's just tight to fit your hands in.
I normally remove the hoses first and let it drain out onto the street, or into the gutter (where ever it seems like a greenpeace guy might be watching), then remove the nuts from the engine fan, then undo the fan shroud, and lift out the fan shroud and fan at the same time.
Now unbolt the radiator from it's upper mounts and lift that sucka outta there. If you've got an automatic, then that's your PITA to deal with because you'll have cooling lines running into it that you'll also have to remove and drain and spill tranny fluid all over your good shoes. If it's a 5-speed, then it should only take an hour from start to finish to swap it all out.
You may be able to get away with doing this without removing the belt (it can hold the pulley in place by the tension that's on it), but if you have to remove it, it's not hard either.
BTW, it's a great time to change the timing belt since you'll have good access to it. When i do a timing belt in these, i'll pull out the radiator just for more access, since it doesn't take that long.
MAKE SURE when you put the radiator back in place that the rubber pieces are in the holes that the radiator lines back into. When i bought my current sidekick, someone had not put one back in at some point, and it wore through the radiator and developed a slow leak.