Mike writes mile-by-mile guides & maps for drivers. He can create a personal itenerary for you - & your pets!
It is rare to stumble across hotels that don't have wireless Internet. However, hot springs hotels seem to be behind the times - or ahead of them, depending on your point of view. A few aguas termales hotels had Internet access in the lobbies, almost none had it in the rooms. If you are lucky and have a Telcel affiliated phone, you could use your phone, but you can't even count on that. Other than those special circumstances, most hotels do have Internet and sometimes it is even fast.
Gone are the days when finding an Internet connection in Mexico meant trekking down to an Internet Cafe. While there are still Internet cafes around, their numbers are dwindling. Why? More Mexicans can afford Internet in their houses. More hotels of all price ranges offer wireless Internet Inalámbrico (though there are serious drawbacks to it, see this page on Internet Inalámbrico.
Many restaurants, including fast food ones, now offer wireless Internet, just as in the USA. Starbucks naturally has wireless Internet, but so do dozens of others. Thus both Mexicans and tourists can connect wirelessly with their iPad, iPhones, cell phones in general and laptop computers. You can use your laptop / tablet / phone to connect at a coffee shop and make a hotel reservation with the Booking.com link on most pages of my site and save a bundle on hotel rooms, even the same day. IF the hotel gives you any grief, there is a phone number under the "?" icon for immediate help.
I've found a good range extender or travel router to be invaluable. Shop below for some good ones.
Need or want a new laptop for your trip? Amazon has decent prices and fast shipping (even better if you join Prime).
If your hotel does not have Internet access, it must be cheap and old. I stay at middle-class hotels (around USD$30-45) and always have Internet connections. You can even drive around some cities and snag an Internet connection from local businesses on your cell phone or tablet.
RV parks also offer Internet access, but, because of the distance they have to cover, lots farther away from the office will have a weaker Internet signal, if any at all.
So do not worry about being able to connect in Mexico. Worry instead about whether you should be online or living in the present moment and appreciating Mexico. Ah, but I digress. I personally save my Internet use in Mexico for evenings after a day of enjoying Mexico.Tablets / Laptop Cases / Geeky Stuff like bed tables for laptops (which I ordered, really cool)