First off let me say that you picked a great hotel. You are within walking distance of almost everything downtown San Diego has to offer. Walk around Seaport Village and browse the unique shops they have there. That will kill about two hours.Next walk north a few blocks and take a Harbor Excursion Cruise to see San Diego from offshore. It s a good photo opportunity. San Diego looks very different from the waterside. Tours run either 1 or 2 hours in duration. Cost is $20-$25. Check it out here: http://www.sdhe.com/san-diego-harbor-tou��Another way to kill an entire day would be to take a cab to Balboa Park and visit the museums and the Zoo. This area is less than four miles from the Gaslamp area where you will be staying. I wouldn t recommend walking because it s uphill. You could take a bus, but a cab ride is nicer and only a few dollars more.When you re done pick any of the Bistros in the Gaslamp area and have lunch, sit in a sidewalk patio area and order a Margarita or two. The hotel will have these little tour booklets for you to peruse through when you check in. If anything else strikes your fancy...Go for it!
Seaport Village is nice. It has tons of cute quaint shops along a beautiful sea wall looking out to Coronado Island. Coronado is also a great place to visit. Ocean Beach is great and also has tons of shops. Balboa park is beautiful place to relax and spend time outside. The Gaslamp District is also full of things to do and see.
Lucky you. That s a great location. When you re done with the Gaslamp Quarter and Horton Plaza you can walk or take the trolley to Little Italy - lots of great little restaurants and some really cool little boutiques. Then hop back on the Trolley and go over to Old Town and if you still haven t had enough shopping, you can take the trolley all the way to Fashion Valley.
Seaport Village, then cruise over to Coronado on the water taxi. Enjoy!