it's pretty easy. just take your time. get about 20 feet of 1/4" standard black fuel hose from auto parts store and a box of stainless steel hose clamps. some guys say to just use zip ties. make sure you replace them one at a time so you don't get confused. you dont need to replace the couple that are vent lines. i did my first ski 2 years ago, same symtoms as yours. took a while because the whole engine was new to me. i did my 2nd ski last week, took about an hour or so to do most of the lines. the real short ones under the air intake and the long one that disappears under the front of the engine i will change when i take the carbs off to clean this week. those ones are easy to change once you got things disassembled to clean the carbs. i also found it to be a little easier to drop the fuel selector valve out of the hull to get easier access to that end of the hoses. (pop the rubber cap out of the center, take the screw out, lift out the knob, remove the hex nut and the valve drops down). make sure your selector valve isn't clogged up while you got it out. you do have to be a bit of a contortionist, or have long arms (which i dont) to work on these things. half the time you can't see what you are working on so you learn to do it by feel.
you are going to want to clean the carb filters after the hoses are replaced.
after that is done look for the thread that describes how to clean your RAVE valves.
