For the main attractions, such as plazas, churches etc, exploring by foot is fine. There are colectivos that ply the main routes, ferrying passengers between the main plaza and bus stations etc.
Comitan is a pleasant and affluent colonial style city that can be a nice alternative to San Cristobal de las Casas. It has a very laid back and friendly atmosphere, with several nice plazas and beautiful churches. It is a good launching off point for a number of sites in Chiapas, and is on route from and to Guatemala.
Stroll around the main plazas, explore the city by foot, enjoy the laid-back atmosphere.
There are plenty of restaurants around the main plaza opposite the church. If you want cheaper food you can find some basic tacos etc in the market (walk past the the church in the main square on the left side and the market will be on your right). There are also a few small street vendors around for snacks like tacos, etc.
There are two budget hotels with (very) basic rooms with shared bathrooms located on the same street as Posada Las Flores for M$70.00. One is called Posada Panamericana and is nearest central park. The one nearest Las Flores was noisy and the bathrooms have seen better days.
OCC and several private mini-bus operations service surrounding locales, including the Mexican-Guatemalan border and San Cristóbal de las Casas. Their terminals are located on Boulevard Belisario Dominguez Sur. To get to the jungle lake of Laguna Miramar from Comitan it is necessary to take a colectivo to the small town of Las Margaritas from where there is a second colectivo to San Quentin (6 hours). It is a 1 km walk from San Quentin to the village of Emiliano Zapata from where you can hire a guide to take you throug the Lacondon jungle to Laguna Miramar. For colectivos to Osocingo, there is a different terminal and you should probably take taxi (its about a half hour walk, ask locals for directions).