It looks to me like I need a new radiator (and might as well do the timing belt), but based off of the pictures, do you think it's much more severe? Thanks!




Sorry for the low res pics, CL won't let me upload HEIC images.

 

I'd replace the hoses and the radiator cap while you are at it too.

 

This is actually fairly common, although yours does look fairly extreme.
By chance have you recently topped off the fluid in the reservoir? The reservoir is an overflow tank which, when cool, should be only about 1/3 full. This gives expanded hot coolant a place to go when the engine warms up. If the reservoir is full the fluid is forced out through the reservoir cap (which is just a snap-fit) and the tiny hoses attached to the reservoir. Once the fluid escapes the serpentine belt movement sprays it everywhere making it look much worse than it actually is.

Notice how the top of the reservoir is at the center of the mess.
I'd clean up the expelled coolant, check the level is correct, then drive it carefully (locally) and see what happens.

 

Is there fluid in the radiator under the cap?

 

Rehab the entire cooling system. It''s probably due. In my experience with Toyotas, once you get north of 140K or so, it's time for a new radiator, hoses, T-stat, etc. If a timing belt is due, might as well address that along with the water pump and the serpentine belt.