Welcome. The Enduro season just ended; the new season will start around September of this year and run through the Spring of 2015. Most of the enduros are in Texas, with many of them in West Texas (the area east of Lubbock). The new schedule should be posted in the next few months. During the summer TSCEC avoids racing in the heat, many of the hare scramble series take a summer break as well.
For prep I would recommend riding as much as possible, focusing on trying to ride 50 miles to get used to the number of miles you'll ride in an Enduro. When you go to your first couple of enduros sign up in one of the C Classes to get a feel for the distance and what it's like to race an Enduro.
Welcome again.
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Jim