You mentioned dread of long stretches of grass. Buy Repels!
Seriously, that skips 90% of the useless animations.
If you find yourself underleveled, just use X-Items, those are busted.
For the Elite Four use the legendary Pokémon Rayquaza, it’s overleveled in Emerald at level 70. If you don’t want to use legendaries, you can use Linoone to sweep the the whole Elite Four.