What about the Mr Whopper? I haven't come across in my travels yet, any ideas

I found it driving on the main Prawn Island road. It seems to appear late at night.

buy the ice cream shop on the second island. Instant Mr. Whoopee!

Take the boat with the spoiler. Though the boat with the big engine is easier to control and looks faster, it's way too slow to do this mission.

Remember that without gas, the boat doesn't steer worth a damn. It's very counter-intuitive, but lay on the throttle early on, and never let off unless you absolutely have to -- and that should be very, very rarely.

I used the first person view, as it's easier to tell if you're lined up properly for jumps and checkpoints. Don't rely on it to spot checkpoints, though. Learn to rely on the radar. I used the radar to get the initial turns, and only used the actual view once I was lined up with the checkpoint.

Again, hammer the throttle. You cannot steer without it, and the boat handles well enough at top speed that you should never have to slow down to avoid anything. If you're having a very hard time with this mission, try running it once without ever letting off the throttle. I had to do that once to drill into my head that the boat doesn't need to slow down -- and incidentally, that's when I won it.... with 45 seconds to spare.

A Malibu mission takes place there, and you can also do the shooting range challenge separately. If you make a high enough score, you no longer have to wait to reload your gun.

I presume I just walk in with a rifle to try it out then, correct?

Just to be clear, we're talking about two different things here:
1) The Shooter: This is the Malibu mission. You get the mission like all the other Malibu missions from a pink mission marker in the Malibu club. It sends you to the Ammu-nation shooting range to do a mission. The mission involves going through three rooms, trying to beat a certain score. It isn't really hard. I think it's the 2nd of the 4 Malibu missions.

2) The shooting range: This mission takes place only in the 1st room of the shooting range. There's a pink mission marker in the room, just like any other mission. Just walk into it. I don't know if the mission only appears after you do the Malibu mission or not... that's when I did it, anyway. This mission is really hard, or at least it was for me. You have to beat a certain percentage, but if you do so, you don't ever have to reload (that rocks on the rockets launcher... rapid fire rockets). It took me about 20 tries... if you fail, just run out of the room and run back in... the pink glowing marker will reappear. One tip: there are three targets, each made up of 5 squares... one head square, and 4 body squares. The closest target is worth one point. The middle target is worth two points. And the farthest target is worth three. To beat this mission, you have to focus on getting the farthest target as many times as possible. My advice is to shoot out the four body squares on the closest target... otherwise, it will block your shots as it moves back and forth. As long as you don't shoot the head on the close target, the other squares won't come back.

The gun you're going to be using is the Python (Magnum), but it switches to the 1st person view for these missions. There's no autotargeting or zooming, so it's basically a single fire assault rifle.