You base weight (all gear excluding food and water)for all of your gear does not need to be more than 15lbs.
For a sleeping bag the liners are almost useless compared to what they weigh. For the Rockies you need a 0C bad minimum. Take a look at the MEC Merlin bags for reasonably affordable, quality down bags. An alternative is a quilt.
Www.enlightenedequipment.com makes really high quality sleeping quilts at a reasonable price. I have ones for my kids as they wouldnt sleep in their bags.
For a pack if you can keep your total weight under 30lbs the Osprey Exos series is great and lightweight. 30lbs is 15lbs gear, 5days food 2lbs per day and 2 L of water.
One of the biggest ways to lighten your load is bring less stuff. So for cooking use a canister stove instead of a white gas stove and just bring 1 pot and one spoon and eat out of the pot or freezer bags. You dddont need a fork, spoon, plate, knife, and 2 pots, and a frying pan.
For clothes you only need the following
Worn
Pants
Shirt
Socks
Packed
Rain coat
Rain\wind pants
Insulation layer (fleece or down jacket)
Underwear ( 1 pair)
Socks 1 pair
long johns
You wash the socks and underwear you aren't wearing while you go. you wash your only shirt as you hike. Anything more than the above is a luxury and extra weight. For a rain coat that is low cost and Lightweight I recommend the Outdoor Research helium. Only 7oz and since here you get more storms than continuous rain the lack of pitzips isn't a big deal.
Start a spreadsheet and put down everything you are going to put in your pack. The cut, cut, cut. If you are interested I can post my gear list which is about 10lbs total gear assuming I split the tent weight with someone else and is as fully functional as others heavier packs. So don't worry about 50, go for 25 and at most 30 total weight.