Network Design – Fault Tolerance

Hello,
I’m networking a 2-store pizza cafe, that are about 10 miles apart.
The owner wants to provide continuous service during ALL hours of business.
The owner wants his customers to have Internet/web access to his cafe’s
menus.
I want to design the network as follows:

If one server should fail in one cafe, the server in the other cafe will
handle the load for both cafe’s.
What do I need to have in place?
Where can I find information/resources on how-to do this??

—
Charles L. Phillips