Hi,
You can get away with "regular" home mechanic kinds of tools if you don't mind being a little creative. For example, a hydraulic press isn't absolutely necessary if you make a "press" with some heavy threaded stock, nuts and many washers for pressing the bearings into the housing. If you're REALLY careful, you can also drive the bearings in with a hardwood block (pressing's best, of course!)
You will probably have to be a bit innovative getting the stub axle pulled far enough thru the hub that the main axle nut and washer can be used to finish the job. (Watch the final torque spec--go over rather than under if you must to get the slots aligned for the cotter.) Short bits of pipe can be helpful as spacers. Other than that, take it slow and easy, and with a bit of care you should be fine. Also, don't skimp on bearing grease, and be sure to use new grease seals. You see lots of posts about Subie wheel bearings--there are lots of "causes" mentioned for failure, but if well greased, and properly sealed to keep moisture out, bearings SHOULD have a good service life.
Also, the roll pin that holds the inner joint to the trans is a one way fit: the holes are tapered, so if it only goes a little less than half way in, stop, drive it back out, move the outer shell 180 deg on the inner splines, and reinstall the roll pin. It shouldn't be too hard to drive in--excessive force says something's not lined up properly.
Good luck, and ask more questions if you get stuck!
Rick