You are exactly correct in what to do.
While you have it open this far you might as well repack the hub. It is not very hard to do. You can follow the instructions on the Park Tool website for
hubs.
To get the adjustment correct, it would be very helpful if you purchased some cone wrenches. They are thin wrenches that can fit on the flats of the cone while you use a second wrench to tighten down the locknut.
The front hub is pretty much the same.
Good Luck.