1) get a tablet with a good battery and storage upgrade capacity. Very VERY handy. I have an ASUS MeMo pad and I love it.
2) Get a good lithium-ion backup. One that can be recharged via solar is a bonus (or one of those "winders" that you can generate energy by cranking). This way, you can keep your phone and table charged.
3) Make sure your carrier supports hotspot on your phone. I use T-Mobile. It allows hotspots from my phone over 4G LTE. It's fast.
4) Backup important gaming stuff to the tablet's storage. That way, if the InterTubes is down, you can still run the game.
5) Use Evernote!! It runs on PC, iOS and Android. You can keep all your notes there and it backs up to the cloud and syncs to all your devices. I have no idea how people run games without it! :-) I prep on my computer, sync to my tablet and laptop, and then I can prep on the go or run a game.
Technology is revolutionizing how we play RPGs, prep and GM. I am gearing up to create a mini-PC with 4 monitor outs. 3 for me (smaller, lower), one player-facing to share maps, images, etc. I plan to dig a little deeper into Realm Works software, but I haven't had time to kick the tires on it. It has a built in mechanism for sharing material with the players. I like the flexibility of being able to search a PDF, take notes (I can actually read later :-), and share images. I also have a nice selection of music and soundtracks to set the mood. :-)
I still prefer in person, so for me the technology is a tool to enhance the game.