All of the functionality can be done via ADSI and / or WMI and COM calls. However the main thing that DUMPSEC is for is for creating a readable report of ACL permissions which would be quite difficult to duplicate in as nice a format as DUMPSEC already has.

There are many ways to accomplish what you're looking to do but you need to first analyze what data you want and why you want it. You may find that you really don't need some data that you thought you needed.

You can query the heck out of the AD and get back just about anything.

First layout what you want and then start working on the pieces to put it all together.

There are IP UDFS, @SITE macro, InContainer, etc... but without knowing specifically what you want and why you want it makes it difficult to suggest the best method.