Is the prepositional phrase adjective or adverb? Why

[Kingterpreter]

Hi, I come across the following sentence when reading the novel Wingfeather Saga:

“With Nugget at her side and all manner of roots and rocks to hold, she seemed more like she was taking a stroll through a park than edging along a perch above the Dark Sea.”

Is the phrase at the beginning “With Nugget at her side and all manner of roots and rocks to hold” an adjective describing the pronoun she? Or an adverbial describing the main clause? Or either?

Thank you

[Alan]

Adverbial, since it specifies why she seemed as she did.
(Cf. adjectival: the girl with the red cheeks)