Peggy --

Burial in a 'National' cemetery usually means the man in question isn't a Southerner. For a specific date of death, you should order a military service file, which can be done here. Once you have the soldier's military unit designation, it's not going to be difficult to locate a unit history which will provide the other information you mentioned.

Links for other message boards appear in the upper left corner of the home page. You'll find them quite helpful for inquiries about soldiers from Northern states.