I started running out of money, so I finally went through the Victory Road to beat the trainers there. Saw Wally at the exit and obliterated his team with Froslass, I've always felt bad for that kid lol but oh well. Before I challenged the E4 though, I went around Hoenn and caught every DexNav exclusive Pokémon, I also evolved some along the way to make some progress with my living dex. After that, I entered the league at last and swept everyone's teams easily, as my Pokémon are already Lv75-80 at this point.
I'm waiting for the credits to roll as I'm typing this. I think I'll go straight for the Delta episode and stick a Wailmer in my team to evolve it in the mean time, so that I'll be able to activate the Regis later.