How does Winnie respond when the Tucks take her home to meet Angus?

I'm not 100% sure if you are referring to the moment when the Tucks "kidnap" Winnie from the woods or when they decide to actually take her home with them.  The two occasions are separated by the Tucks' explanation of the spring water and their resulting immortality.  I'll go ahead and give Winnie's feelings for both.  

When the Tucks first scoop up and take Winnie with them, she is not as scared as she thinks that she should be.  

Winnie had often been haunted by visions of what it would be like to be kidnapped. But none of her visions had been like this, with her kidnappers just as alarmed as she was herself.

Winnie admits that she has thought about being kidnapped before, and she uses the word "haunted."  She anticipates being scared, but she is not scared now that she is actually being kidnapped.  The reason for that is because the Tucks are more frightened than her.  Winnie's feelings are probably closer to shock and surprise.  The text says that Winnie was even calm about the entire situation.  

Winnie herself was speechless. She clung to the saddle and gave herself up to the astonishing fact that, though her heart was pounding and her backbone felt like a pipe full of cold running water, her head was fiercely calm.

After the Tucks' explanation of their immortality, it was decided that the group should head to the Tuck house.  Winnie's feelings are completely different now.  She's calm, she's happy, she's excited, etc.  She lets Miles carry her and even falls asleep in his arms.  Gone are the thoughts of being kidnapped.  Instead, now Winnie has convinced herself that she is running away like she had planned to do.  Only this time, she has company.  

And Winnie, laughing at him, lost the last of her alarm. They were friends, her friends. She was running away after all, but she was not alone. Closing the gate on her oldest fears as she had closed the gate of her own fenced yard, she discovered the wings she'd always wished she had. And all at once she was elated.

I always get the feeling that Winnie has convinced herself that, in a way, the Tuck family is rescuing her.  

. . . Winnie put vanity aside and dozed gratefully in Miles's strong arms, her own arms wound around his neck.