Um I'd have to say quite the work out since you are in the water the entire time.  I think they wear fins too and that can be tiring if you aren't used to swimming with fins on.  Wear your knee and elbow pads and obviously head gear.  And a hard bottomed board.

I have not experienced the luxury of a board while swimming, but it looks like quite an improvement.

I've shared surfing spots with riverboarders and the occasional meltdown spot like Flipper on the Ocoee. It looks entertaining enough.

There was someone running classes on the Ottawa. Sometimes a dozen at a time. I've got a bit of video, but nothing exciting.

I don't think any special skills are required, other than pretty good knowledge of whitewater stuff in general and "specific knowledge and experience of the individual run".

I say "specific knowledge and experience of the individual run" because you ain't going to see much. Your line of sight is going to be severely limited and scouting is going to be a pain because standing up and walking around with the flippers is not going to be an improvement.

The good news is, the flippers are a vast improvement when swimming. I have swam in current with flippers and you can really boogie.

A nice, thick wet suit will provide some extra buoyancy. I haven't noticed actual knee pads, but instead, wet suits with beefy knee pads. This is definitely not an ELF thing.

Your board should suffice as elbow pads, though I have seen boardies, especially classes of boardies wearing them.

I've toyed with the idea and have missed a couple chances to buy a board. Looks like they're $400+ retail. You could build your own, using a 2'x4'x3"(more or less to suit) chunk of minicel. Cut it down a bit for size and shape and gluing it to a dead hull or other suitably flat piece of plastic. Webbing & tubing for the handles. The tough part is going to be figuring out a good cup holder.

Good luck and keep us posted.

Thanks for the input Dale, I hadnt actually thought of the line of sight aspect in the big picture since most videos make it look like a stop and run each rapid kind of thing regroup and move on. The fluid anvil looks like the rolls royce of river boards compared to a lot of the foam ones Ive seen home made. But I also hadnt thought of the dead hull idea!!! I have a bliss stick mystic that has a great hull up front... sounds like i need to experiment myself!

No tall drops.  Ran boulder drop on the Sky, but not at big water.  Floated the Selway last spring on it...learned it really isn't for that. I'm part of a rafting club, so I'm planning on bringing it with.  Make sure ya got flipper tethers