Most travellers reach Tapalpa from Guadalajara. The drive takes about two hours in normal conditions, first south from the city and then up into the mountains.
Second-class buses run from Guadalajara's southern bus terminals toward Tapalpa and nearby towns in southern Jalisco. Check times before setting out, because service is useful but not as frequent as routes between larger cities.
A car is helpful if you want to visit Las Piedrotas, Salto del Nogal, or La Ceja without arranging local transport.