Not that I'm there yet but I was wondering whether you can continue the game once you have completed the main story. I'm leaving exploring the tombs for now and plan to explore them at the end of the game but am concerned that the game will not let me go back the tombs/continue to explore once I've finished the quest.

Not sure if when you finish you able to return to go tomb raiding :X and collectible collecting.

I do know you will come to a camp or campfire that say's it's "the point of no return".

Perhaps to can fast travel and do all the tombs and collectibles then fast track back there.

Once you finish the game you'll be able to load your last save and continue searching for collectibles

There you go someone will usually have the answer

Thanks folks, all makes sense.