Are there already models for planning and goal-directed behaviour?
Reward systems are one of the most actively studied topics in (cognitive) neuroscience and prediction error - that is, deviations from expected "future" reward - play a big role in that. Since you're particularly interested in models, I recommend checking out the work of Matt Botvinick and Nathaniel Daw. Here are a few papers that might be good starting points:

Glascher, Daw, Dayan, &amp; O’Doherty (2010). States versus Rewards: Dissociable Neural
Prediction Error Signals Underlying Model-Based and Model-Free Reinforcement Learning. Neuron, 66, 585-595.

den Ouden, Friston, Daw, McIntosh, &amp; Stephan (2009). A Dual Role for Prediction Error in
Associative Learning. Cerebral Cortex, 19, 1175-1185.

Solway &amp; Botvinick (2012). Goal-directed decision making as probabilistic inference: A computational framework and potential neural correlates. Psycholological Review, 119, 120-154.

Botvinick &amp; Plaut (2004). Doing without schema hierarchies: A recurrent connectionist approach to routine sequential action and its pathologies. Psychological Review, 111, 395-429.