Been doing installs in every conceivable vehicle on earth for 40 years+.
Start by taking any speakers and lights that are recessed in the ceiling loose. Most of them can dangle. This often allows you access to places unseen.
Be patient and have a helper. You may need to drill some of your own holes but be very careful. One drill bit in the wrong place can be a disaster.
Take the plastic pillars off each side near the windshield before starting too. Wiggle any existing wires and listen closely how they are routed.
I have some handy pulling tools such as an old speedometer cable. Those are amazing things. Be very very patient.
