If you don't have a way to remote to your PC, then you're mostly out of luck. I ran a setup very similar to what you're talking about when we went to the beach a few months back. My IP is mostly static so I didn't need to set up DynDNS or anything on my router. I think you'll find this article very helpful but it will more than likely be something you have to do when you get back for the next time.
There have since been 2-3 XBOne system updates that might make this more stable or less stable, but I had a solid few days of being able to log in and play with barely any lag. It was really amazing since the internet speed at the ocean wasn't great. Towards the end of our vacation I ran into an issue where I could no longer log in as I think something on the XBOne got hung up and needed to be hard reset. Still, I think that remote gaming on the XBOne isn't that far off if MS wanted to officially support it.