Given that many trainers let's you immediately have a rematch I don't think the game is very difficult, for that fight against Team Rocket specifically I remember you can fight a trainer with a butterfree and a scyther on route to Mt Moon for massive exprience. There is a benefit if it's...
Found a potential bug in The Viridian Forest. The trainer with a Pinsir and a Butterfree will continue to give you a leaf stone every time you talk with him.
edit:
Got this error message when I used the area finder in the pokedex for Scyther as well.