Hi, A.!
Have you ever tried a ring sling at all? I know that I once looked at several backpack carriers & found that they were all SO heavy that they were just not a possibility for me to deal with. I, however, used my ring sling either on my hips or on my back & did much better with that. Plus, since a ring sling allows for so many different positions, I found that once my daughter started to feel to heavy, that I could switch sides that she was on or switch the position that she was in & that would relieve my discomfort.
At the risk of spamming myself, I actually make baby slings & have a little company called THING-A-MA-SLING. Last month, we took a family trip to FL & I carried my son (who was probably about 16 lbs) in my sling for 10 hours straight, 3 days in a row & my back was fine! I couldn't believe it! My back is notorious for being bad & it was fine!
If you live locally, (I live in Easton), I'd be happy to meet with you one day so that you can try out a sling if you think you might be interested. I also invite you to check out my site: www.ThingaMaSling.com in the meantime if you would like to. Most of my inventory is not on there, but there is a link to view some of it on there.
Where is the veggie stand located? I love buying local, fresh veggies!!!
Good luck!
A.