1. Through Brock and Misty
Starting us off with the redos, here's Geodude to start us off with. I don't have much trouble since much of the start of the game is just trading Normal attacks back and forth. I do try to ensure that I'm going to have enough HP to make it through Brock, because I didn't want to wait until level 16 to learn Rock Throw. I enter the gym at level 13, and make it through the trainer with no problem. The battle with Brock kinda sucks, and I probably should have just grinded to make it through, but I spent all my money on Potions so I was certain I'd be okay. Unfortunately, that Geodude at the start took all but 1 PP of Tackle, so Struggle tactics it is against Onix. Yay, burning through Potions.
Misty was likely to be a painpoint, but I had decided to hold off on Geodude evolving to Graveler until after learning Earthquake at level 31. I have two Rare Candies, so I need to get to level 29 first, so I go ahead and do the entire route to Bill's first. This gets me to L28 after defeating the Dig TM thief. I debated about teaching this to Graveler, but decided to instead teach it to Onix so it had a good STAB move. So, I take out the gym trainers and that gets me to L29, then I pop the two Rare Candies, get to Level 31, learn Earthquake, and evolve to Graveler. I'm now able to survive and OHKO both of Misty's mons with a single Earthquake. Noice.
2. Through Surge and Erika
It's at this point, things accelerate. I fight all the trainers in the S.S. Anne, then grab a Spearow and trade for Farfetch'd. I teach it Cut, head into the Electric Gym and take on Lt. Surge. One guess how well Earthquake worked.
At Rock Tunnel, I pick up a low level Onix, teach it Dig, and head back out. I spend a couple of hours getting it up to about L25 (which is nothing compared to Graveler now being L39). I figure this is enough and go through the Rock Tunnel with little problem. It's nice doing this (again) because I remember the way through this time. Hooray muscle memory. I take on all the trainers heading west from Lavender Town on the way to Celadon City, and then I do the entire Team Rock plotline in the town before moving on to face Erika. After taking down all of the trainers in the gym, Graveler is now L41 (Rock Throw, Mega Punch, Tackle, and EQ) and Onix is L35 (Rock Throw, Slam, Dig, and Rage). I let Onix do as much Digging as possible, and then when it goes down, I switch to EQ with Graveler. Easy enough.
3. Through Koga and Blaine
I do the Pokemon Tower stuff, and then head south since I'm lazy and didn't pick up the bike. Longer route, but more XP available. I decide to hold off on fighting many trainers until after I pick up my next mon in Fuschia. Well, more correctly, the Safari Zone. There, I get a Rhyhorn, and spend some time leveling it up so it can evolve. This allows me to get it a moveset of Stomp, Ice Beam, Thunderbolt, and Surf. Of course, Koga is just Dig and EQ. It's about this time I wish I had been catching Pokemon the whole game to get 50 for the Exp All item.
I fly back to Pewter, pick up the Old Amber, and then just over to Pallet Town and surf down to Cinnibar. I take my Helix Fossil and the Old Amber to be brought back to life, and I now have my entire team. I spend a little bit of time moving my way through the little dungeon there as I head for the Secret Key, eventually having Omanyte evolve to Omastar and Aerodactyl getting a few levels. Graveler's at 44, Onix L41, Rhydon L43, Aerodactly L32, and Omastar L42. Decent levels to take down Blaine.
4. Through Sabrina and Giovanni
So much XP in this part, and Aerodactyl gets a lot of it. I let it grind through the Fighting Dojo, then I get lots of levels and finish up the Rocket Plotline. From there, it's on to Sabrina, and this is probably just a little bit of frustration. Some of her team have low defense, but they hit hard because my team has low Special. Except for Omastar, but I didn't want to have to put that one in play unless I had to. Still, got through it on the first attempt, so can't argue with progress.
Some of the trainers in Giovanni's gym have fighting types, so I let Aerodactyl take the lead. Also helps to be a Flying type as well in a Ground gym. It does get knocked out during the gym leader fight, so I just switch over to Omastar since it has Bubblebeam and that's nice enough to take down the rest of the team.
5. Elite Four and Champion
For Lorelei, I start with Omastar and use Withdraw, boosting my stats. Then I use Spike Cannon to do some nice damage. Obviously, it keeps trigging Rest on Dewgong, so I instead switch over to using Hydro Pump, and that's enough to break the chain and I progress on. The rest of the team isn't much to worry about, other than Lapras, but that's just cause it's tanky. A couple of Thunderbolts from Rhydon (especially one that paralyzes and one that crits) take it down.
For Bruno, Aerodactly and Omastar all the way.
For Agatha, I sort of have to deal with the the constant switching as best I can. I'd like to use Dig or Earthquake, but if the Ghosts are going to be swapped out for a Fly-er, I don't want to go that route. I decide to just spam Rock Slide (Rhydon), which is actually a pretty powerful. But, it is Rock, so it's like "super power, rare hit chance".
Lance is the only one that I have to adjust strategy for. True, I have Ice Beam on my Rhydon, but there's something in the way - the Gyarados. So, Omastar first, and do whatever I can to take down the Gyarados, then I just let whatever goes down go down. The Dragonair on his team go down fairly easily, and the Dragonite goes down to a couple of Ice Beam uses from Rhydon.
As for the Champion, well, Aerodactyl to start, then when it goes down, Omastar. From there, it's just Onix, and Rhydon, and finally, it comes down to my Graveler against a Blastoise. It tries to use Hydro Pump, and misses...giving me the chance to use EQ to knock it out for the win.
Wasn't too bad of a run, but the grind is slow.