Sounds like you need to replace your hoses, and since you're doing so you might as well take the radiator out to clean up where the hoses attach. If it's really that baked on, I'd cut the hoses off with a box knife, remove the radiator and gently cut the old hose away from where they attach to the radiator.

It's easy to remove the radiator: remove the coolant hoses, remove the transmission cooling hoses (at the bottom), remove the long bolt that holds the oil cooler (that little radiator that attaches to the main radiator on the driver's side) at the bottom of the oil cooler, slide the oil cooler up and off the radiator, remove the two clips at the top of the radiator, push the fan shroud out of the way and the radiator lifts right out.

You'll lose a little ATF in the process, so be sure to top it off when you're done. BTW, I do not recall seeing a drain plug on the Behr unit I just installed.