If you're missing anything, you can now use the extensive network of camps to fast travel between the areas to take care of unfinished business. Even if you have 100%, I encourage you to do this in order to see a final cutscene with Lara and Sofia back in the Geothermal Valley near the Valley Farmstead Base Camp. Then you'll have the opportunity to reload your last save.
After the end credits, there's a short cutscene with Lara and Ana after the events in the Chamber of Souls. When you finish the game, it autosaves in the same slot you were using previously.
