1. He's uncertain about his future in Preston, Virginia.
Throughout the section about Jamie Sabin, the narrator repeats the word "unknown". This indicates that he is uncertain about his future in Virginia. He may also be looking forward to his new life, but there are not many words with positive connotations that would indicate that it's going to be a "great new life".
2. a. Blue smoke
The wake of the bus leaves behind a blue smoke. It says that this smoke is full of these "abandoned hopes, and intentions half-formed".
3. "long olive fingers pressed nervously against the tote bag"
This best shows that she is tense since it describes her fingers as "pressed nervously". This pressure indicates that she is tense. The line "pained furrows between her brows" can indicate that she is anxious or worried, but might not be the best evidence to show her as tense and possibly unhappy.
4. b. The concept of home
Jamie Sabin is described as "going home to a place unknown". This description of him "going home" is used twice in the section that describes him. Kathryn Shay is described as "running away from a home too well known". These two passages both show different types of homes.