My sleeping bag, backpack, shelter, and sleep pad weighs 10 pounds. A well fitted pack is definitely easier on the back and take tons of pressure off the shoulders. You can get a two person tent that weighs 2.5 pounds to 3 pounds for under $300.00 I know Tarp Tent has one in that criteria. It go a long way in reducing stress on you two's backs. There a lot of links under Ultralight Gear on the left that lead you to some products that are extremely lightweight.

Welcome to the forum and hope you and your wife enjoy the hobby!
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It is one of the blessings of wilderness life that it shows us how few things we need in order to be perfectly happy.-- Horace Kephart