[blackedoutharley]

On the rear I believe you're going to find that removing the axles (8 bolts in the center) is required to get the drum off. Check those bearings out at the same time and replace as needed.

For the front I would pull the dust cap and remove the hub and drum together. That way you're forced to inspect the bearings and replace as needed or at the least, repack them and install new seals.
Once you have the drum/hub off the truck it is much easier to separate them while on a bench.

While you have it all apart it would be a good time to replace the wheel studs as well.... they do get weak with age you know.

If you have the funds, why not replace the shocks (that look original) while you're in there?