Sorry but when you put "brute force" and "coherent logic" in the same sentence , the result will be "incoherent". Brute force is the lack of a algorithm that has a logic; if there is one, then the logic part comes in. For #66 there is no other way of cracking it apart from brute force ! Any reduction technique that you think it will work, it won't,  because all we have is the output of RIPEMD160(SHA256(Public Key)). Unless you broke SHA256 and RIPEMD160 all together and somehow managed to recreate the 256 bits input from a 160 bits output, then this is pointless.  As you could see from other posts, people have tried already all sorts of techniques : statistical analysis regarding keys distribution in a certain range, "magic" relationships between wallet keys (with or without the knowledge of Pub Key), etc.

Try to read more about address generation process. One you've done, move on to the signature generation part where you can read about other interesting potential vulnerabilities like nonce reuse , nonce share , lattices and so on ! You will see how interesting the secp256k1 curve really is !

Cheers!