My Gold version turned 10 years old in August, so a few weeks ago I decided to play it for a bit. I started the game up (internal battery is still alive despite being ancient) and looked at what Pokemon I had in my party. I noticed that I had a Chikorita that I'd traded over from my dead Crystal version earlier this year, so I decided to go train it. First, I flew to Mt. Silver and leveled it up against some of the wild Pokemon there. Once it had evolved into Bayleef and was level 20 something, I went to the Pokemon League and beat the Elite Four. By the time I finished doing that, Bayleef had evolved into Meganium.