I went back through Jagged Pass, now with the acro bike, in order to collect the remaining items I had previously missed. I also attempted to return the meteorite to Prof Cozmo, but he didn't take it back. Either I've visited him too early, or you pick up the Return TM in a different location. I then challenged the 4th Gym, where I struggled due to not having a decent water or ground type, but still managed to defeat Flannery on my first attempt. I declined May's offer to be transported to Petalburg city as I wanted to explore the desert route first.
Here I caught a Trapinch, who will become a part of my final team, and chose the Claw Fossile over the Root Fossil. While training up Trapinch so she was the same level as the rest of my team, I used to time to hatch the Wynaut egg and evolve a few more Pokemon to assist with Pokedex completion. I then returned to Lavaridge to talk to May, once again just in case using her to be transported to Petalburg also triggers other necessary events.
Challenging Norman's gym was incredibly easy due to my Combusken, who evolved into Blaziken during the final gym trainer fight. Norman managed to be somewhat easy thanks to my Beautifly getting lucky with Silver Wind and raising all her stats three times during the fight. Once I received the Surf HM I was transported to Mauville via Wally, where I then crossed to the other side of Route 118 in order to grab the Good Rod. I ended up spending about an hour and a half looking for a Carvanha, who will be replacing Skitty in my team. I'm now spending the time to train up my new Carvanha so his levels match the rest of my team, as well as training up other Pokemon for Dex completion.
My team is currently:
Bandit / Carvanha Lv. 27 [M] (Surf / Assurance / Swagger / Ice Fang)
Rose / Manetric Lv. 33 [F] (Discharge / Bite / Quick Attack / Thunder Wave)
Burnie / Blaziken Lv. 36 [M] (Scratch / Peck / Blaze Kick / Double Kick)
Kazoku / Trapinch Lv. 34 [F] (Earthquake / Crunch / Rock Slide / Earth Power)
Mephis / Sableye Lv. 34 [M] (Feint Attack / Confuse Ray / Night Shade / Shadow Claw)
Vil / Shiny Beautifly Lv. 34 [M] (Tackle / Air Cutter / Silver Wind / Giga Drain)