Complex sentence: The Sourland Mountain location, while secluded, afforded easy access by air and automobile to the Lindberghs'offices in New York City and to the laboratories of nearby Princeton University, to which the Lindberghs' had been granted access.
Split into simpler sentences: The Sourland Mountain location, while secluded, also afforded easy access by air and automobile to their offices in New York City. It provided proximity to the laboratories of nearby Princeton University, to which the Lindberghs' had been granted access.