I've never had to opportunity to hunt elk, but a 280 will certainly shorten the like span of a bull mose in a hurry. Shot placement always critical regardless of calibre. http://www.chuckhawks.com/280Rem.htm
280 Remington shooting 160-gr. Nosler AccuBonds or Partitions is great elk medicine. If this fine cartridge had been introduced 3 years earlier, then Winchester might not have even brought the 270 to market and we'd be ranting about the improved 280 Rem rather than the 270.
When it comes to scent, there are basically two types; those that attract and those that mask. I've tried both on many occasions. There are lots and lots of "doe in heat" scents, designed to attract a big buck into range. I've also used a "cow in heat" scent while elk hunting.
Another scent would almost be better named as a "coverup smell". The main goal is to cover up human odor or mask it. Though I don't believe you can ever totally eliminate all human...