re: How many miles is too many on a used truck?

Fiancée has a 2004 regular cab/bed Silverado with a 5.3L in it, almost 190k miles and she's convinced it will die any day now. She has an easy commute, never abused the truck, never hauled more one small U-haul trailer, has religiously changed the oil every 5K with Mobil 1 5W30, and every other fluid has been regularly serviced with OEM fluids. Replaced the water pump and alternator once with OEM parts. That truck will run another 200K without trouble.