The link above is the standard map that pops up everywhere.
Envision the parents and extended family of over 1200 plebes-to-be all headed in roughly the same direction to the same places, and you will find your way to Alumni Hall, the Mid Store, Dahlgren Hall and all the usual spots. People in uniform who work on the Yard are used to being asked questions, and there will be many veteran/alumni parents around staffing Parents Club tables or being plebe parents themselves.
If you get in the night before, have a nice dinner downtown, and walk onto the Yard to do advance reconnaissance - a "recon."