Hey Roux!
Signing on for a sec just to make some recs...
Have you tried any of Bailey's stories? She has a large selection of fics, all well written and plenty of finished ones.
Just Another New Kid in Town is a great place to start, over 30 chapters, about a high school age Jack and Ennis, Jack just moves to town, is pretty poor, meets star baseball player Ennis who is just as cannon and withdrawn as ever. Bailey does an amazing job writing these boys. Her current WIP I'll Be Seeing You is also very good. It isn't complete, but it's over 40 chapters right now, and I think she said she has about 9 more to go.
Have you read The Wolf and the Thunderbird by kumari, Camden Yards' author? It also isn't complete, but she is getting ready to post the last 2 chapters and epilogue all at once in a couple of weeks she said, so, by the time you finish what is already there you won't have long to wait. This is one of my favorite fics and favorite Jack incarnations. It's dark, but well worth it. A 17 year old Jack and 21 year old Ennis set in 70's Texas.
Beans and Crazies is the ultimate AU if you ask me. It's by Montana Crows and Jack and Ennis set up a life together right off the mountain on a ranch in Montana, and it is literally about day to day life on the ranch but it is incredibly well written, she has Jack and Ennis spot on and knows ranch life because she's actually lived it. It isn't finished yet because this is literally the fic that will never end, but it's well into 60 chapters now, so plenty to take up your time. Updates come slowly now though because Montana Crows is actually in Iraq.
The Greatest Love by Cynical21 or her newest The Short Leash both cannon, both short but complete, both spectacularly written. Cyn is one of the fandom's best writers, IMO.
Those are just off the top of my head. I know I didn't give you many finished ones... if I can think of any more I'll let you know.
Oh, and for AU!AU RPS, Bailey's The Raw Prawn!! My favorite in RPS next to The Bellwether/Ronin (though I also love Down the Mountain/Water Walking which I see you're already reading...)