Hi Dan,
When X-Plane crashes, please send the automatic crash report. If possible, save the log.txt file from the crash without re-starting X-Plane. If you use a Mac, submit the crash log.txt & Apple crash report on our bug reporter. If you can reproduce the crash and provide us exact steps, that can be helpful as well.
Otherwise, you can try moving your preferences folder to the desktop and restarting X-Plane to see if that helps the long load times. You can also try moving plugins & custom scenery out of the X-Plane folder to see if that's affecting it.