A Little Reassurance and Advice
Although Chiapas and Tabasco are off-the-beaten path for Americans, they are not for other travelers, so you can be assured of finding the necessary travel services, such as banks, hotels, Internet cafés, and tourist offices. San Cristóbal de las Casas is especially geared toward travelers. The only places you won't find such amenities are the indigenous villages.
Bus and car travel throughout the region are options for exploring; use caution, never drive outside cities and towns after dark, and watch out for slick roads during the rainy season. If twisting mountain roads aren't for you, air travel is an alternative, though it won't take you to the small towns or ruins. Tuxtla Gutiérrez and Villahermosa have airports, handling predominantly domestic flights.
If you're looking for the ideal hub for exploring Chiapas, consider San Cristóbal. Whatever you do, you won't want to miss seeing surrounding ruins, notably the Mayan city of Palenque.