Yes, even the best of us have been known to slip and fall during a dicey stream ford--been there, done that! Anything that shouldn't get wet should either be inside a waterproof pack liner or a dry bag. Both should be tested before each trip, just to be sure. My critical insulation all survived the dunking and stayed perfectly dry, even with several inches of water sloshing in the bottom of my pack (where the sleeping bag was). There are a number of commercial pack liners, or you can use a 2 mil trash compactor bag (make sure it's unscented; a lot of them these days are perfumed) or cut down a 2 to 2.5 mil contractor trash bag to fit your pack. To line smaller pockets, turkey roasting bags are great. You might check out Nylofume pack liner bags which have had some great reviews and are reportedly sturdier and more odor-resistant than the somewhat overrated OP sacks.

My only electronic devices are my camera and PLB. Each of those is in its inividual padded ziplock bag.

I do use a pack cover but that's only because I use my pack as a pillow at night and don't want my sleeping bag rubbing on a wet surface. I don't count on the pack liner to keep anything but the front and sides of the pack dry. It certainly won't keep the pack contents dry in case of immersion or heavy sustained rain. However, with the pack cover on, you can lean the pack against a tree or log at night in such a way that the uncovered back side is underneath and doesn't get wet. The other possibility is to put your pack inside the pack liner bag at night (turning the pack liner inside out if the pack is wet). You do need to be careful not to get the inside surface of the pack liner wet, though. You can get pack covers weighing 1 oz. or pack liners weighing 2 oz., the latter with a dry bag closure, from ZPacks. I highly recommend their work. My only relationship with them is as a very satisfied customer.