Once out of a boat, you become the boat.  The first step is to ensure your PFD is up to the task.  Once each year, test your PFD for adequate buoyancy.  When immersed in deep still water, does your head stick out of the water or have you sunk to your eyeballs.  Some PFDs lose their buoyancy over time and you definitely don't want that kind of surprise when you really need to float high (like swimming a rapid in big water).

If the PFD checks out, how should you swim with equipment?  In general, hang on to that boat and paddle.  Many paddles are black in color and really blend in well with water.  I swear this is a conspiracy - LOL.  Add bright stickers or some light colored duct tape in the middle of the shaft so you can easily spot a lost paddle.  The boat can be an asset in big turbulent water as it provides extra flotation.  Always keep the boat below you so you don't get sandwiched between the boat and a rock.  When close to shore, toss the paddle on shore like a spear.  You can also push the boat into shore and swim after it.

Mixing defensive and aggressive swimming techniques allows you to get yourself and equipment quickly to shore.  Judicious aggressive swimming (pretending you are a boat) along with rock scrambles and wading can get you to places in a rapid that are very difficult to reach by boat.  Set-up time is nil in most cases so it comes in handy when you need to get someone on a trapped boater quickly.

The wet exit is a skill paddlers at ALL levels need to know.  Granted, expert boaters avoid this last resort with solid rolls most of the time.  The first step is to immediately get in a tight tucked position - kiss the deck.  This protects your face, arms, body, etc.  When you bang the bottom of the river, your helmet and PFD should decent protection.  The next step is getting some attention - knock on the side of your boat with your fist.  If lucky, someone may give you a bow rescue.  You can sweep alongside your boat with hands perpendicular to grab the rescue bow.  Oh well, no one came - now what?  Grab the side of your boat cockpit and move the free hand forward to find the release strap.  Pull the strap and push the boat off like you would get out of a pair of long pants.  A quick somersault under water and you head to the surface.  Hold on the paddle and head to the upstream end of the boat.  Survey the situation to determine your next best course of action.  Here is a nice video demonstration: Wet Exit Demo.