Bella had travelled and she didn't inform anyone that she would be going as she knew that if she told even a single person then Allison would find out about her absence.
She couldn't risk it and she would rather be seen as a traitor than let harm come to the people she had grown to love.
It was a risky situation because she didn't know how she would be received but she wasn't scared as she had made up her mind that this was something that she had to do.
She knew she didn't have the luxury to be afraid, this was something she had to do and if fear was the one thing that was going to keep her away then there was no point in going.
The journey wasn't an easy one, she had to scale through a few obstacles but thanks to the knowledge she had about zombie guts, zombies were the least of her problems.
She didn't take the shorter route because there was a chance that Allison had people stationed there and she couldn't risk being seen.
