An Ant Colony to solve a word problem

I have modified my ant colony to solve 4 letter word problems of the type:
Starting with the word "leaf", changing 1 letter per step end with the work "loan" e.g.
leaf -> lean -> loan

I also have versions that solve 5, 6 and 7 letter problems, although for 6 and 7 letter words (and probably 5 too) there are so few connections between words, you might as well brute force your way through it.

The problem with the following characteristics seem ideally suited to an Ant Colonies:

1. definite routes between points
   
2. required to optimise for shortest route
3. large problem area - for small problems, just brute force it.
   

Again, code available on request.