After the dark mark was cast at the quidditch world cup, the Weasleys et al waited for a portkey but......Arthur, Bill, Charlie and Percy could all apparate. So why not take the other 6 by side along apparition instead? Arthur (say) could take Fred, return for George return for one more while the others take one each.
Seems far simpler to me!
But I am a bit of an asshole for plot holes in HP. Dont get me started on the Egypt holiday money issue!