Maybe this is the time for you to look into an Amtrak vacation, especially if it is not something you’ve done before. Many North American destination cities are easily accessible by train. Getting there can be half the fun on some of the more scenic routes.
San Diego is one of the best-loved vacation destinations in the US The train runs right into the middle of town, with easy local public transportation to get you to your hotel and most of the attractions. San Diego is spread out over a smaller geographical area than other parts of SoCal, notably Los Angeles. In fact, a lot of the attractions can be enjoyed by walking.
San Diego is really loaded with interesting places to visit. You could really spend weeks at all the museums, historical places of interest, beaches, theme parks and other attractions. So it is safe to assume that you can engage yourself in a week of both relaxation and activity in this harbor city. The weather in the summer is particularly appealing, with a moderate sea breeze cooling things off.
If you wanted to make it a more extensive trip, it is possible to continue the train travel up to the Los Angeles area, and beyond that up the West Coast. AmTrak runs from the downtown San Diego station to downtown Los Angeles Union Station with a few stops in between. By doing any of the above, it would be reasonable to engage in a one- or two-week vacation without using a car.
Don’t forget that a trip by train can add several days on to the total schedule compared to flying, but if you have the right mindset the traveling can be part of the overall enjoyment of the trip.