Agree on the master. I'll add it to the list of things to address next year, or sooner, if needed...

Those temps are bothersome as it was during normal driving at speed, just me in the car, a pretty cool CA night. 204, up to 206. That means my trany temps are likely to get higher than what they should too. Load-up the family of four and our stuff for snow country... I need to check that t-stat.

I'll order a factory t-stat. I guess I need a gasket too? A new radiator will have a new cap, I would think. Might as well since I need a new radiator anyways (brown top, as you noticed). Upper and lower hoses, good idea. We actually "make" distilled water at home. It's literally on tap. I'll buy some coolant...

If the map lights are the ones up by the rear view mirror, by the moonroof controls, those are not the festoon type in my truck. The dome lights are though...

Looks like I can get the factory rad for 110 bucks here:

https://toyotaparts.bochtoyotasouth....YT10b3lvdGE%3D

Edit / Add: Checked a couple local Toyota dealerships and they want like 220 bucks for a radiator; and will not price match.