I had at one point traded two Pokemon for a schyther and venemoth level 78 each. I swept everyone but now I want to play normally. However now all my Pokemon are around the 40's and I have to face Pokemon in the 50s. I am up to waking the snorelax of digglet cave and I discovered and went through every other route, beating every trainer there is. Where should I grind with those levels
Try getting the numbers of the Gym Leaders in the Pokegear in order to rematch them. You can find them all over Johto and Kanto at certain times of the day. Here is the guide for rematching the Gym Leaders. Every gym leader you rematch has Pokemon from Levels 48-62, except for Blue, who has Pokemon from level 68-72. Good luck!