Well if you want to use that vs. seeker for cash, to buy protein, carbos, etc. then try this method:
Fly to Hearthhome city, go south of the city onto route 212, once you get near the mansion, you should find 2 old people staring at eachother, they both have 1 pokemon each, which usually range from lv. 20-70 (They level with your pokemon). By beating each one of these people you get 12, 000 pokepointz, and if you go to amity square and roam around, you should eventually find an amulet coin, which doubles the cash given, so every time you beat one of them, you get a whopping 24,000 pokepointz. Keep repeating for desired money, (VS seeker).
If you want to generally train your pokemon but you do not have enough lv.s to beat the elite 4, then generally, keep vs seeking trainers on Victory Road, the give good xp, and to make a long trip, stock up on revives and hyperpotions/full restores. (Use method stated above).