I just finished my annual backpacking trip in the Wind River Mountains (WY).  We backpacked over 40 miles.  It was some of the most rugged terrain I have ever been in.  While many on this forum are aware of weight and quality issues with gear, I wanted to emphasize a few points:

1) decent pack - this is the foundation of any plan to pack gear cross country.  Get a decent pack.  I have a Gregory Baltoro 75 for my multi day trips.  For over nighters I use an Eagle assault pack, but weight is much less of a concern.  Regardless, don't cheap out on your pack.  Durability and light weight are critical, followed by comfort.  Even a few miles with an ill fitting pack will beat you up.

2) weapon portage - what is your setup?   Let me start by saying that humping a rifle will be a PITA.  Even a pistol becomes heavy when hiking with a 30+ pound pack.  If you don't condition yourself to carry your BOB and weapon, you need to.  Do not delude yourself into thinking your gear setup is adequate just because you tried it on in front of a mirror in your house.  Get out and pack it around.  It is the only way to know what really will work.  When wearing a pack, I use an Eagle paratrooper holster with the leg strap removed and adjusted so it rides just below my pack belt.  I have tried chest rigs and the like and they usually interfere with the pack or my breathing.  It may work for others but not me.  Whatever you get, make sure it is comfortable and functional.

3) gear - go as light as possible, and minimize.   MRE's and para cord are bulky and add weight.  3mm cord and dry foods are effective and will take up less space and are significantly lighter.   Shaving off weight on a couple items won't help much, but when you shave weight on all of your gear it can easy add up to several pounds.  

4) fitness - it takes energy to carry weight over time and distance, more than you think.  Get fit.  An obese man carrying a heavy pack on foot is a poor bug out plan.  Lose the extra pounds and practice carrying your BOB to get used to it.  

5) make sure it works - use your BOB.  Go take it on a day long hike, and use it's contents.  This will help you learn what works and what doesn't work.  A heavy pack full of unused gear would be a disaster.  A light pack full of functional gear is an asset.

Anyway, those are my thoughts.  My BOB weighs 15 pounds.  It is enough to get me by for a couple days.  I know I will be somewhat uncomfortable compared to what I take backpacking, but I have gone out and survived on it for a couple days and it works.  It's light, and I can cover ground quickly with it.  Please feel free to add any other suggestions, but these are the basics to make a BOB effective IMO.