I have created a Project from an Event of a vacation. Without proper planning, I have an edited Project that is 3 hours long. I cannot find info on how to split/divide this large project into 3 or 4 smaller Projects, apart from making 3 or 4 copies and blade cutting away to achieve a more manageable time file size for final editing.

I've attached a FCPX course on working in the Timeline (above), maybe there'll be something helpful in there.. I'm an audio guy myself, but the approach you mentioned would seem to me to be the most straightforward way to go about it..