Randy - I agree with ButterBean and Joe. However since you are hunting in Wyoming plan on wind! That is why I would go with the 154 HHT. I've only hunted antelope in Wyoming. I'm not sure where in Tennessee you are from, but if you are not from the top of the Smoky Mountains, you need to prepare for elevation. All of Wyoming is over 4,000 feet! Also prepare for elevation gain. Where I hunt elk right now, I can be anywhere from 2,700 feet to 8,400 feet all in the same day! That is not on an ATV either, it is hoofing it! Hit the stairs as much as you can! Do you have access to a stair stepper? If it is blowing out, time to get out and practice! I would also add try to do some shooting downhill and uphill. Level shots are a rare occurrence here in the West.
I wasn't going to share this, but I think it might be both an encouragement and a motivation for more load development. Most of my elk have been shot with my 30/06 Ackley Improved. My load? All but one were shot with the180 grain Hornady Spire Point going 3,000 fps muzzle velocity. So my question to you is are you satisfied shooting your 300 RUM at 30/06 AI velocities? I think this shows how much you are leaving on the table. The good news is I know from experience that load will kill elk. So if you stick with the load you shared, I think you will be OK. I just hate seeing the RUM so throttled down. Last but not least. If you drop down to the 137 or the 154 you will be pleasantly surprised at how much less recoil you will experience.
Most important!!!! Have fun on your hunt!