I've only died, 5-7 times I think this time, which is something for me to be proud of.
Also, during the Guardian Digger battles, as with all enemies in that maze, just use PSI Freeze. Use PSI Freeze a on the small ones (like the snakes, ducks, and noose men), and PSI Freeze b on the Guardian Diggers. Make sure Ness has a Bionic Slingshot, and have Jeff use bottle rockets (though the bigger the better) against the Diggers, and just have him shoot the other enemies. Bombs help against all the enemies (Diggers and others) too. Needless to say I was just prepared for the desert this time. I honestly didn't take much more than 130 HP damage in that maze, and Lifeup doesn't use much PP, so none of my friends died as opposed to my last run through there.
But Moonside's still dreadful. I'm having a hard time remembering where everything is...and I'm pretty sure I'm gonna die again when I get to the Mani Mani Statue. That thing beat me down (5 times I think) the first time I went through.