Don’t connect to the internet. If you need it for reference or reading, gather it before your “work session” where you want to get in the zone. If you need Internet (ie for what you are working on) simply don’t open a browser, or if you need it for work as well, don’t open other tabs.

I always take a laptop camping, but it’s a outdoor converted (Pixel Qi display) circa ‘08 netbook. Its slow but fast enough, and I do a lot of great work on it, distraction free with no internet connection in the woods.