We arrived in San Diego around 1pm and did not want to waste the day, so settled on a trip around the park.
There is ample parking and many parking areas that are free for what I can remember, was as long as you needed. We strolled through the grounds from the aircraft museum up to the Botanical Gardens. The façade of the museums is worth a visit, let alone going in. You can buy a ticket that gives you access to all of the museums, rather than pay individually.