Sorry to disappoint you, but a very similar program already exists. Google "Freelancer Companion".
There are certain points of data it can't handle, namely diplomacy, but you can manually exclude any given faction's bases from a trade route. It also doesn't handle the legal status of commodities, since those are subject to mod/server rules, but once again particular commodities can be excluded from calculations.
Importantly, the program reads the game files itself (rather than the data needing to be copied across manually), so that it can be used with nearly any Freelancer mod.