meaning of a sentence

[KLPNO]

Hello everyone
I'd like to ask about the meaning of the following sentence from a SF story.

Calculating how far he had come, he saw that most of the world lay behind him now, while it wasn't too much of a lie to tell himself that Port of Krauss was waiting just beyond the horizon.

Does the phrase "it wasn't too much of a lie" mean, in this case, "it is not a big exaggeration"? And if so, why the author uses "while" after saying "he saw that most of the world lay behind him now".

In other words, it seems to me (if I understand the sentence correctly) that "and" is more natural instead of "while". If "most of the world lay behind him now" it implies, in my opinion, that Port of Krauss wasn't too far from him and using of "while" is unclear to me.

[Mister Micawber]

.
Here, 'while' means 'and', roughly. Here is the dictionary definition: at the same time that (showing an analogous or corresponding action): The floor was strewn with books, while magazines covered the tables.
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_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber

[KLPNO]