I'm not sure this counts but PokéMMO is great, you will need to have several Pokémon game ROMS because with PokéMMO you are actually playing those games in a massively multiplayer environment, not singleplayer, this means you can play with friends or even make new friends in the game, you can trade and battle with other players and when you process enough in a region you can go to the next one, you do not have to complete one region before going to another so if you don't feel like playing generation 1 then just progress enough to get on a boat and go to whatever generation you want to play in the moment.

Make your way to the edge of the galaxy... you'll waste so much of your time doing the same thing over and over, worth the weeks it will take!