There is no order. It depends what missions you do first.
it would take a long time to say every single one, they are found scattered all over the place though and are very common
You can do missions for Bonnie MacFarlane in Red Dead Redemption, that is all.
Do your missions.
do your missions
yes
No, in undead nightmare you basically kill zombies and do zombie missions
on the storyline there is 51 missions and 18 side missions
you have to do missions
i have both and i believe red dead redemption is a lot better as on mafia a lot of the missions are very similar whereas there is a lot more variety in red dead redemption. also red dead redemption has a much better and interactive environment
do the missions which it says in your journal
You must complete the main campaign missions in order to get access across these "borken bridges"
there is no cheat for it, you must do the missions for it in your journal
you must do more missions until it unlocks