Ken,
I've done mine and it is doable if you're the mechanically inclined type. A couple of pointers though:
1. There's a stainless steel or brass spacer on the stub axle. Don't assume that the one you have now will work on your new hub assembly. They come in thickness ranging from .110 to .138 inches thick. You must measure and get the right one.
2. ERA has some pointers on how to set the bearing up right. Check out this info:
http://erareplicas.com/427man/jagrear/rhub_axle.htm
3. You don't need to have a press or pay someone to press the bearing on or off.
4. To get the wheel hub flange off the hub, just rest the angled side of the hub on a step and use a hammer to tap the hub flange off. Works like a charm.
5. If you're replacing the outer wheel bearing, you will need to rent a bearing puller to pull the outer wheel bearing off the hub flange. I think I payed about $5 to rent one.
6. You don't need to press the new bearing on either. Just put the hub flange in the freezer for a couple of hours and the new bearing in your oven set at about 150F for a few minutes. The bearing should slide right on or need just a slight tapping to get it on.
Chris