I am late to the thread, but I was reading what you were saying about the walks...not getting 1/4 of a mile unless you pulled or used some force with the dog.
Here is my question....so you only get 1/4 of a mile right now...so what? Is it necessary to go for long, long walks right now? And if your dog can't go for long long walks without eating trash and pulling, then why force her/him to do something that she/he can't succeed at? I used to do this with my dog and it would frustrate me to no end, but for what? Why did I need my dog to walk 2 blocks without pulling? No reason really, other than to fulfill my expectation of what walking a dog "should" be like "at this moment".
I am just going to give you my two cents, it's not the gospel but just my experience: My dog is part border collie. He can be a real pain on walks. He pulls, tries to eat every single stick, leaf, piece of garbage, etc. that he can find. And he barks at cars in an attempt to "herd" them. It's pretty frustrating at times. However, my experience with positive reinforcement has been great. Yes, it has taken longer than I would have liked. But it was training that I was comfortable with. My dog and I couldn't even walk 1 block initially. So we built up to longer walks. And some days, he is so distracted, so trash-grabby, that we go for really short walks until he is calmer. I know now it's not good to walk him right when I get home from work, because he's too excited to see me. We have to wait 30-45 minutes until the novelty of OWNER'S HOME!!!! wears off.
Our walks have been the best "leave it/drop it/sit/stay" training opportunity. I bring treats, and reward him for not picking up garbage, or for dropping a cigarette butt. We practice sit/stays on corners before we cross the street. Walks have also been a great training technique for reactivity. It has really proofed his behaviors. So again, be patient if you are choosing to use positive reinforcement. Progress can be slower than we'd like, but it does work. My dog still pulls sometimes (especially on trash day), but it's ok because he used to pull ALL the time. He barks at every 8th car, but that's ok because he used to bark and chase EVERY car. If you are going to stick with positive reinforcement, just know it takes time. Just wanted to offer some support regarding the amount of time it can take to get a dog to learn via positive reinforcement!! I had to stop putting my expectations of what I thought my dog should be like on him and meet him where he was at.