I put this list together to help myself, but thought why not share it with the gaming community. Most credit can go to chimera_80 I just did the editing and added some tips. I don't have a map, though I'm sure one will show up soon. Anyway, if I had a map I would just make it a FAQ and not a sticky :D
Some of the Stranger missions have requirements before they can be unlocked (found under Complete ____) After you find the mission at the starting location, the next part of the quest (if there is one) will appear on your map as a purple circle or as a question mark.
Some quests take a few days to be able to move on. You can easily avoid this by reloading your last autosave (the game will save after each stranger encounter) and more often than not, the next part of the mission will be available.
Again, credit to chimera_80 for most of the following information.
Flowers For a Lady Complete "New Friends Old Problems" Starting location: Between Macfarlane's ranch & Thieves landing.
Let No Man Put Asunder Complete "Obstacles in Our Path" Starting location: Near Coot's Chapel
Jenny’s Faith Complete "This is Armadillo, USA" Starting location: East of Ridgewood Farm
California Complete "Women & Cattle" Starting location: South of Gaptooth Breach
Water and Honesty Complete "Political Realities in Armadillo" Starting location: East of Coot's Chapel up on the ridge along the path.
American Appetites Complete "Political Realities in Armadillo" Starting location: Outside Sheriff's office in Armadillo
Funny Man Complete "Exhuming and Other Fine Hobbies" Starting location: Telegraph Office in Benedict Point
Who Are You to Judge? Complete "Liars, Cheats and Other Fine Americans" Starting location: Rathskeller Fork
Lights, Camera, Action Complete "The Sport of Kings and Liars" Starting location: Movie House in Armadillo
I Know You Complete "A Tempest Looms" *ONLY as John Marston* Starting location: South of Mescalero
Deadalus And Son Complete "We Shall be Together in Paradise" Starting location: On the ridge just east of Agave Viejo
Eva In Peril Complete "Lucky in Love" Starting location: Behind Cantina in Casa Madrugada
Poppycock Complete "Civilization, At Any Price" Starting location: Chuparosa
Love is The Opiate Complete "Empty Promises" AND Stranger 13 "Poppycock" Starting location: Beside the slaughterhouse in El Matadero
AWESOME, this list just helped me 100% the game. i was at 99.5% & didn't know what i'd missed. i read that there are 18 stranger missions & my stats said i had 18, but that was including "i know you" so i didn't know what i'd missed until i stumbled upon this list you got here. just wanted to say thanx man....