I have been playing my Red version again over the past couple of days. I decided that I was finally going to raise one of my Pokemon to level 100 since Gen I is the only generation where I've never had a lv. 100. ;_;
Anyway, I've chosen to do this on Red since I have the Jynx from the ingame trade on my main team, so it gets boosted experience. When I started playing again, it was level 61. The first thing I did was do another run of the Elite Four, which allowed Jynx to grow several levels, though I don't remember how many. Yesterday, I went over to Cerulean Cave and spent quite a while training against the wild Pokemon there. I managed to get Jynx to level 74 and will hopefully continue training it soon.