During the escape from Jakku, Rey flies the Millennium Falcon through a rear booster of a crashed Super Star Destroyer. She flies inside that ship a fair distance with plenty of clearance.
I know that Disney scrapped the majority of Star Wars canon, and so previously-published schematics of ships may no longer hold canon value. However, I'm willing to accept any officially-published schematic, regardless of current canon status.
Basically, I'm wondering if her flight path through the Super Star Destroyer would have been possible using what we already knew, or if we have to assume that Disney canon has new schematics.
We know the ship has been scavenged for a considerable time, but looking at the flight video, we see areas that appear to already be hallways/tunnels/access paths already large enough to easily accommodate the MF. All of this takes place in the very rear of the SSD.
This clip, starting at 3:49 and running to 4:12, shows the flight. So, we have at least 20 seconds of flight time along a mostly-straight path. For those without video access, here are some key images from this flight showing that the path is primarily intact and looks like the open spaces were designed to be open, rather than having been scavenged (which, given the dimensions, is also unlikely to have occurred, anyway).
Rey enters the engine pictured in the center here, although a few seconds after this shot. This shot gives a better overview of the structure.
This large obstacle is still present (not scavenged/destroyed), and still there's plenty of room to maneuver.
This "door" and other designs seems to indicate the space was meant to accommodate large ships, or simply be spacious.
The large open access port here may give clues as to location?
Rey exits here, but you can see that the path she was on, parallel to the "pipes" we see in most of the scene, continues a bit further into the distance.