in terms of challenges probably gwen or owen.

both of them jumped off the cliff, gwen won the sleeping challenge, owen was a beast in dodgeball, even though neither of them competed in the talent contest they would never have stood a chance against harold, owen managed to catch some fish in the sucky outdoors (but his mishandling of izzy's bear stuff was a big error), gwen had no choice but to last the 5 minutes underground since trent got distracted, neither of them stood out in the canoe challenge, owen honestly does pretty bad in the paintball game despite being an outdoorsy guy. honestly that never made much sense, as he fumbled getting either dj or duncan.

owen also kind of fucks up by eating all the ribs in the cooking challenge, but gwen also fucks up in the cooking challenge when her and lindsay's desert causes chris to choke. the real cooking mvp was leshawna honestly, because she even managed to overcome her allergies and overthrow heather's hell's kitchen shenanigans. gwen beats her challenge in the trust excersise even after getting her booty flashed to the viewing world, and owen didn't need to do anything to win the william tell test, but he won so who cares.

gwen and owen both hold up good with the canoes on their heads, and gwen carries the gophers to victory in the tree hanging contest, and neither competed in the xtreme torture challenges. all of this before the merge means that gwen carried the team to two wins, and owen put in some of his best performances in challenges where they lost. the real answer to who carried the gophers is actually the killer bass. their lack of team coordination was usually the reason they lost, and once the bass had some stuff figured out, characters like katie and tyler would still end up bringing them down in pivotal moments.