Fluttering over the water pit about breaks even with carefully timed jumps out of the water.  You can also swim through the whole pit and not lose very much time. The sheep crab blocking the tunnel can either be damage boosted through, or killed with 3 egg shots. For the boss, you generally won't be hit while standing in the middle. However, the boss dies in 6-7 egg shots if you ricochet them up into the side of the uvula. Do this rather than throwing eggs straight up at the bottom of the uvula, which takes many more egg shots to kill the boss.
It is possible to kill Froggy in 5 shots with very precise egg angles (see IL record). The distance that the egg is from the uvula and its velocity on the frame of impact determines how much damage is done. The 5 shot strat uses a 45 degree angle and specific Yoshi positioning to get the greatest possible distance between the egg and the uvula while also ensuring that the egg has the highest possible X & Y velocity.
Even if you're not going for 5-shot, some runners like to do a few of these 45-degree shots and then stay in the middle for the last couple, once the acid drops become harder to avoid. This makes killing Froggy in 6 shots much easier than if you stay in the middle for the whole fight.