I may have found some answers for you. I need to break up the information into two posts.
1. A prepositional phrase (preposition + object) sometimes acts like a single adverb.
Tom went there.
Tom went to France. / to his mother's home.
Do you see how the preposition phrases are something like the adverb "there"? So they modify the verb. They answer the
question: Where did Tom go?
Therefore, "to France" and "to his mother's home" are not the objects of the verb "went."
If you have any questions, please do ask. I or someone else will be delighted to try to answer you.
Reference: Guide to Modern English by Richard K. Corbin, Marguerite Blough, and Howard Vander Beek, copyright 1965, 1960 by Scott, Foresman and Company, page 301.
P.S. Those sentences above are mine. The authors' examples were:
Ed went home.
Ed went to his house.
"Home" in that sentence is considered an "adverb."