Doesn't sound too bad. I've seen dealer coupons for $250 timing belt replacements.
I'd recommend a factory water pump since they are high quality and come with a really good stainless steel/rubber gasket.

And since you mentioned 200k and wanting your truck to last, you might want to think about having them replace the timing belt pulley's while they're at it too. It will probably add another $2-300. Cam and front main seals too...? It starts to add up.
That stuff is the kind of thing you can take a look at when you do it yourself and decide whether or not they might need it though.