Once again this is a request of my younger brother (i was bribed with chocolate) ye so here is his team to face the elite 4 with:
Dialga
Lv:53
attacks: Blizzard, Ancient power, dragon claw, roar of time
Garchomp
lv: 54
attacks: Dragon claw, dragon rage, crunch, dig
Lucario
lv:55
attacks: aura sphere, extreme speed, dragon pulse, close combat
Staraptor
lv:55
Attacks: aerial ace,fly,close combat, brave bird
Empoleon
lv:55
attacks: surf, waterfall, drill peck,metal claw
Roserade
lv:55
attacks:Aromatherapy,cut,mega drain,giga drain
Chansey
lv:18 (he is training it)
Attacks (that he is goin to get for chansey):Thunder,Flamethrower,surf,giga drain
Now my brother said should he keep chansey (trying to make evolve to a blissey) and replace it with another pokemon or should he stick witht the team he has got? also he needs some good training places (trainers) to train his garchomp and dialga apart from the rich boy fisherman and Beauty on route 222
it looks like a very good team however chansey even when it has evolved it is not a very good attack pokemon. It has a high defense though and health so it would be great to use it in case you have to heal the rest of your pokemon in case they get injured but eventually chansey will faint. Good luck i beat the elite four this same way except insted of having chansey i had a lv. 62 Darkrai. About Places to train i’m not sure