Another very simple idea to construct a model from data (with one continuous target variable) is that of using a regression tree. Matlab provides classregtree functions, aimed at constructing a regression tree. I ran it on my data with this script. The performance graphs are shown below, as well as an exemplary regression tree. There have been no optimisations so far, but the tree has been pruned to reduce its complexity for viewing.

Regression tree, mean absolute errorRegression tree, root mean squared error

Exemplary regression tree