Pokemon Stadium 2 - Gym Leader Castle Round 2 - Transfers ONLY from new game (Yellow) FAQ:

Q: What is this run?
A: Basically, only use transfers to beat Round 2 of the Gym Leader Castle in Stadium 2, while starting from a new file of. So you have to play through the game and build a team to the point you then beat the Gym Leader Castle.

The reason it is transfers only, is because otherwise the fastest method would be to to just use Rentals to avoid the team building altogether.

Q: Why are you using Yellow as the game to get transfer from?
A: So, in Stadium 2, currently I haven't actually completed Round 2 yet. So I can't use Dodrio Tower for GSC. As such I'm limited to using RBY for this at the moment - I actually think at some stage I will redo with GSC (not because it's better - it's actually much worse. But just because it's interesting, and they would be separate types of runs)

Out of RB and Y, I chose Yellow for this time because I think it has some options to better Pokemon for the run.

Q: How are you going so fast in Yellow??
A: That's the Dodrio Tower, a mode in Stadium 1/2 that lets you play RBY at 4x speed, as long as it's connected with a transfer pak.

Q: Is Pokemon Stadium 2 from a new save file as well?
A: No, otherwise you couldn't do Round 2.

Q: Will you do a run of Complete Game with transfers from new game like this?
A: No, because grinding to L100 from Prime Cup would be insanely boring and not fun.

Q: Will you do other cups/parts of the game like this?
A: Yes, I plan on doing Petit Cups too, as well as Little Cups in Stadium 2. Might also do other GLC and Poke Cup stuff, we'll see.

Q: What is the route for the team you want to make?
A: For Gym Leader Castle, the Pokemon you fight are at at least Level 50, and match your highest level. As such, I want to make a few Level 50 Pokemon.

The team I'm going for will consist of 5 of them, and hopefully they will be enough to get me through. The 5 Pokemon I'm going to get will be:

Nidoking (Used throughout the game, caught at Level 4/6 on Route 2)
Starmie (Caught with Super Rod at L40 in Seafoam Islands, is the main reason Yellow > RB, as Staryu is only L15 in those games)
Zapdos (Caught at L50 in Power Plant)
Graveler (Caught at L50 in Cerulean Cave)
Muk (Caught at L41 in Cinnibar Mansion)

Q: Are there any other Pokemon you considered?
A: Yes, but your options are limited on what you can get to a high level reasonably quickly.

The best potential Pokemon would be Snorlax, which you can catch at L30. With STAB Self-destruct and perfect stats to use Counter, it would get 2 kills in a ton of fights, but I'm trying to skip using it because grinding it to L50 takes a ton of time, and it's very bad to use in game to win fights due to being very slow.

Other considerations: Articuno/Moltres (These would get used in Stadium 1, but they are nowhere near as good in Gen 2)
Mewtwo (Would be amazing if caught at L50, bbut givne it comes at L70, it would raise all opponents to L70. As such it would have no support and have to win basically by itself, while Mewtwo is good enough to do that in a lot of fights, it can't in all of them, especially in gen 2 with Dark/Steel introduced)
Weezing: Another boom option, but not available in Yellow. Would maybe get use in a RB run instead of Muk due to level, but Muk's higher Attack and Sp Def make it a more reliable option to kill with imo.

Q: Do you know if this will work?
A: Nope, just mapped out a general idea purely based on theory, I've done no testing at all. Given the nature of this run using multiple games and a transfer pak, the way to test this is with a run