For major legislation, someone may have already compiled the documents, or at least created a list of citations to them.
Checking the sources on this page first may save you lots of time.
The Zief Law Library also has compiled legislative histories on microfiche through Congressional Information Service's CIS Index to Publications of the United States Congress, call number: KF 49 .C62 Law Microforms).
Selected compiled legislative histories are also available in print at the Zief Library. Try a "Doncore" keyword search in Ignacio, and include the phrase "legislative history" in your search.