I plan on replacing the front and rear rubber suspension bushings with roller bearings. Can this be done one at a time without destroying alignment (assuming I do it left and right at the same time)?
Is this a DIY project for a fairly inept home mechanic?

I can be done one at a time but you will need an alignment for sure when you are done. Since you have to remove the control arms to install them, you will be changing the alignment drastically.

you will need an alignment. i'm in the middle of doing this as well. the old bushings can be tough to get out. i found it easier to just drop the whole suspention than fight the bushings and burning them out while everything was on the car. there is a grand total of 10 or 12 bolts and the retaining caps on the bottom of the ball joints and the whole assembly is free. then you can place the whole unit on some saw horses for easy working. this method also allows you to clean things up.

k