Coronado's charm is largely due to it's location and all that it offers in a relatively small area of space. You can drive to it from the San Diego-Coronado Bridge, but if you have the time and want to take in the gorgeous scenery, take the ferry from Broadway Pier instead.
San Diego's unbreakable tie to the military through its presence and significance in the area is recognized and celebrated during Fleet Week, held every September.
Whether the two of you have kids or just love to be around children, a fun date would definitely include stopping into the San Diego Junior Theatre to see one of the troupe's latest productions.