San Miguel de Allende is a relatively small town, so it is easy to walk. Cabs are also readily available and affordable. You can hail one on the street or have your hotel or restaurant call one for you. Another option is to rent a bike to explore the city. Public transportation is limited, but there are local buses that run on certain routes. Keep in mind that the city is hilly, so wear comfortable shoes and be prepared for some inclines when walking or biking.