Doing it all at once is smart, when you can afford to do so. This will mean all the rubber bits on the car are ready to go for another 300K. You will just have to worry about drivetrain maintenance at that point. Replacing one control arm here, one rear link there, will drive you crazy at your mileage. Plus you usually need an alignment after any bushing/arm work.
I would definitely go with Bilstein HD's on all four corners if you have not already replaced the shocks/struts.
Looks like you got most of the pieces. But here are a few things to watch out for.
Rear Subframe mounts (there are four total)
Differential mounts (two)
Rear sway bar bushings/links
I would also buy an "arm kit" for the rear rather than the individual bushings for each arm. This way your mechanic is not going to be wasting time (and your $$) pressing old bushings out and new ones in, this is the biggest time consumer. If he can just rip out all the old arms and bolt all the new arms into place, that will be hours saved.
Wheel bearings are a good idea and easy up front. The rear bearings might eat up a huge chunk of time. If they aren't making any rumbling noise at all, I'd say leave the rears alone for now. It's another thing that can add 4-5 hours (or more) to your bill.
You will have a brand new driving car at the end of it. But since you've owned it from new, you already know how nice it's going to be.
