I caught the bus from Casas Ibanez to Albacete in March, the bus stops about 30 metres to your right as the Camino crosses the main Centro road, there is a timetable there telling you when busses are. I am not sure if tomorrow is a holiday but it's worth checking it out, there may be some form of parade on that main road limiting access to vehicles, these parades will be going on all across Spain . Another option( I think) is to catch the bus going the other way to Valencia, there is trains regularly between Valencia and Alicante.
Buen Camino