Heather
so how big is your current bag and how big are the other bags? Are the newer lighter ones also smaller? Are you ready for smaller or do you just want lighter? Packing small is a thing of its own that many people consider to be a part of backpacking completely separate from being light. Ok everybody knows I have the most expensive pack, big and light and I don't think theres anything wrong big big as long as its light and carries the load. Also for 35 pounds you need a frame of some kind against your back - frankly for your trip to the sierras you might find, as did thousands during the 70s and 80s, that a cheap external frame back with sleeping bag slung under is an excellent way to go carrying a lot of food for long trips, or for those who carried a cast iron frying pan and a gold shovel...
Jim