200k on GMC truck

I have a 2004 3/4 crewcab that has been absolutely awesome. It’s coming up on 200k miles and want to keep it strong for many more years. I won’t be driving it as much but still want it to work as a tow and winter sports vehicle. I’ve been regular on maintenance. I want to keep it reliable on long trips. What kinds of “repairs” should I be proactive about? Timing belt, water pump? Tune up? I’m going to have the ball joints and suspension inspected but are there mechanical items I should be concerned about?

At that mileage and considering the long trip scenario, I would be pro-active on the water pump and change it along with the accessory belt and tensioners if they have never been replaced.
Fuel pumps can be another area to consider being pro-active on; especially if the filter has not been changed on a very regular basis.

Driveshaft U-joints is also something to stay on top of. Many times these are faulty but may feel perfectly tight. The only way of determining this is by removal of the driveshaft.

Change the transmission fluid/filter regularly and even install an aftermarket transmission fluid cooler. These coolers are worth their weight in gold when it comes to extending the lifespan of the transmission. If you trade the truck off in the future you can remove the cooler, reconnect the original cooler lines, and use the cooler on your next vehicle.

I have 3 brothers in law who are in the masonry business (as was their deceased father who also owned a small trucking company). They’ve all used Chevy and GMC pickups in the masonry field and larger GMC trucks in the trucking company. Just about every one of those smaller trucks would get anywhere from 350k to 450k miles put on them before being retired and they did take a beating along the way. I see no reason why your truck won’t go just as far.

Just my opinion and hope it helps in the decision process.

If this engine had a timing belt it would have broken long ago.

Keep doing what you’ve been doing. Follow the factory maintenance schedule and fix anything that breaks.