I usually just sneak straight through Quarry Junction right after leaving Doc Mitchell's and run past the guards at Camp McCarran to take the monorail to the Strip. When you start a new playthrough of New Vegas, where do you go after leaving Goodsprings and why?
I generally follow the quest line to the Strip so I'm high enough level by the time I get to it. I really like Cass so I make it a priority to get her as a companion as early as possible too.