It is very difficult, you have to hate caesar and either want to side with the NCR or want vegas for yourself, you need a high speech, im not sure about science or medicine. When you do get him, keep pushing him to tell you about his past by taking him to places about the enclave or the brotherhood.
You must hire Arcade Gannon as a companion. You can find Arcade with The Followers area inside Freeside.
To begin Arcade Gannon's side quest all you have to do is hire him as a companion. He will then talk to you and he will start the quest. Arcade is located in Old Mormon Fort.
If you feel like killing Arcade Gannon. He isn't able to be your companion after the quest so killing him wont effect anything or make anyone hostile.
You have to hire "Arcade Gannon" and a secret little quest will come along. But you have to talk him into it.
He is at the Old Mormon Fort, which is in Freeside, on the outskirts of New Vegas. It is not a marked location on the map, just part of the Freeside area.
Look up the Quest "For Auld Laye Syne". You have to do a few things with Arcade Gannon in your party and he will give you the key.
The crashed Vertibird
his in the Old Mormon Fort in freeside freeside is next to new vegas
first you need to make arcade gannon your companion then you need to bring him to three places to trigger his memory i know 2 are repfconn headquarters and the crashed vertibird you can look up the other ones then he will give you a quest and follow that to reform the enclave and you will receive the armor
the dog you can apparently get.
Each companion in Fallout New Vegas has a quest (or two).-Arcade Gannon: For Auld Lang Syne-Cass: Hearache By The Number-Veronica: I Could Make You Care (and unmarked quest You Make Me Feel Like A Woman-Raul: Crazy, Crazy, Crazy (and unmarked quest Old School Ghoul)-Boone: One For My Baby and I Forgot To Remember To Forget-Lily: Guess Who I Saw Today (and unmarked quest Lily and Leo)-ED-E: ED-E My Love-Rex: Nothin'But A Hound Dog
Deathclaws. And there weird companion but i dont no that tings name