I think I'd say stone's sheep/moose/caribou in BC on an old school pack train like O'Connor used to do. The rifle for that would be a 270 WCF I suppose... a custom job, maybe on a Springfield '03 action?
Actually I contributed an essay on this topic to the Weatherby Dream Hunt contest. Maybe I didn't win because the rifle in my essay wasn't a Weatherby
In that essay my boys were 13 years older than they are now (18 & 16 rather than 5 & 3) and we took a pack train into the Bitteroot/Selway Range of western Montana. We were on a shiras moose/mule deer combo hunt. It really was more about the boys than the hunting... my dream is that they'll love to hunt like I do, that it'll bring 'em together, and that it'll provide for them a haven of silence and peace from our loud and busy lifestyle.
A .35 Whelen on a Granite Mountain '98 action with a 23" Hart 1/12 barrel stocked in circassian walnut w/ a Leupold Vari-X III scope was my sidearm for that fantasy. My sons had a 270 WCF and 7-08 Rem with them.