as far as inside the hull...
1) its a new ski, shouldn't be that dirty or sludged up... but if you have stuff in the bottom of the bilge, i'd get a gallon of purple power or super clean at wally world, put it in a squirt bottle and spray the bilge, rinse off with a hose or light pressure washer and let it drain out. (some guys like to put an inch of water in and slosh it around, that does help a little to reach spots you can't with that engine in there)
2) if its the engine you want clean, i'd use CRC 6-56, it does an amazing job. My 04 honda's engine looked like it just came out of the crate because CRC had been used on it for all 11 years. you can use a rag/toothbrush/qtip to get the hard to reach spots if you really want to be anal, I just use a soft rag myself. (I bought a gallon of crc which is good for years, but I also use the little aerosol can's that I buy at an auto parts wholesale store off the shelf, again, so I can reach the hard to reach spots)
3) i'm also a fan of fluid film and spray that on the pump, it leaves a residue so I don't spray it on the engine, but I won't hesitate to use it on bolt heads and electrical connections inside and such, but mostly for the pump & all the bolts... It comes in an aerosol can so you can reach the hard to get spots pretty easily.
4) a mechanic friend recommended T-9 spray, but I haven't tried it, I think its similar to crc.
if you really want to hit hard to reach spots you can dump some cleaner in a garden type sprayer that pressurizes, then you can shove that little nozzle down in spots your hand can't reach and get all silly with it.