Hi Scotty88,
The GoPro's are great. I sell them and use them so can offer you a few thoughts.
For your needs, best advice is to buy the Helmet Pro HD. It comes with the camera, two flat mounts, two curved mounts, a "J" mount, a head strap mount and a vented helmet mount. This pack retails for $399 which is just $30 more than the Naked camera which comes with only a single flat mount.
You can buy the surf expansion pack if you like, but I see little point. The actual surf mount (big white disc) is a massive overkill especially on a SUP. The knuckle joint breaks long before the adhesive on the mounts gives way. Once you stick the surf mount down, it is pretty much permanent unless you apply bulk heat.
My vid I popped onto the SUP site (SUP Ningaloo) recently was all filmed with vented helmet mount on my helmet. I also had the head strap but I find the helmet easier, especially coz I run the LCD Bacpac and this restricts the angle you can point "up" on the head mount as the longer rear casing interferes with the mounting. This can be overcome by using a "J" mount but you'd need to buy that as a seperate if you go Surf hero or Naked. You can go nuts with accessories if you have the coin. Another handy one is the tripod mount and also the Grab Bag which contains a 3 way articulated knuckle, a spare standard mount, a flat and a curved adhesive mount but would be a bit unnecessary if you go with the Helmet Hero pack.
The LCD Bacpac is excellent if you have no laptop to review footage or piccies at the beach. You can use the LCD to line up a shot or can sort through footage and review pics and clips as required. It only burns battery if you leave the LCD on. I keep it switched off when not needed which gives normal battery life. When you turn the camera on, the LCD lights up, just push the "off" button on the screen and it shuts off and leaves the camera functioning normally. It's great to be able to see your pics or clips then and there but at $139.95 it is a bit of a luxury.
I would suggest a spare battery would be a good investment at $49.95 and another good accessory would be the ride Hero mount which will clamp the camera to your paddle if you're doing waves.
Make sure you get a decent SD card, only go with Kingston or Sandisk and go with class 4 or better. I run Ultra and Extreme cards and have never had an issue. 16Gb will give you around 4 hours of footage when using R4 or 960 lines. Using R5 or 1080 (Full 1080 line HD) gives you around 2.5 hours which equals about the life of the battery. A 32 Gb card is better that way you don't have to keep dumping the data to a lappy or ext drive.
Another good idea is to take Anti fog kits or a few grains of rice, or a few grains of silica gel as the cameras can mist up and of course they only mist up on the lens :( One friend holds his camera in the aircond duct in his car to cool the camera and dry the air before he closes the housing. It works too.
Anyways, that should give you a few ideas.
Have a great trip and if I can part any other wisdom, please just ask.

DM