Answer:
1. into their covered wagon
2. across the desert
3. ahead of them | to reach the farm
4. on his face
5. with considerable skill
Explanation:
It might be challenging to identify a prepositional phrase when it has some words after it, or when there is a prepositional phrase after it.
For instance, #3 has the phrase “of traveling”, which is part of the bigger phrase “They had days of traveling.” One could end the sentence with “traveling” and that would still be a sentence.
Good luck to you!