The Little Bear NERO Checkpoint at Little Bear Lake in the Cascade is the first checkpoint you open. You do it during the story mission Bugged The Hell Out. It teaches the power-and-speakers routine and gives your first NERO Injector.
The mission walks you through it. Cut or shoot the loudspeakers before you turn the power on, or they blare and draw Freakers. Then get the generator running with fuel, a new fuse or a reconnected cable, depending on the site.
With the power on, the NERO trailer opens. Inside are the NERO Injector, which raises Health, Stamina or Focus, and the Intel Recorder. A powered checkpoint becomes a fast travel point.
The Cascade Radio Tower Ambush Camp is just to the north.
O'Leary Mountain Safehouse
The O'Leary Mountain Safehouse is the converted Forest Service fire lookout Deacon and Boozer live in at the start. It is your first safe place to sleep and save, and it has a stash of crafting loot.
Horse Lake NERO Checkpoint
The Horse Lake NERO Checkpoint is a Cascade checkpoint tied to NERO's body trains. It pays Copeland's Camp and gives you a NERO Injector early in the game.
Old Pioneer Cemetery NERO Checkpoint
The Old Pioneer Cemetery NERO Checkpoint is a Cascade checkpoint at the old Pioneer Cemetery. It pays Copeland's Camp, and its log is one of the first hints of what the Militia is doing to the roads.
Chemult Community College NERO Checkpoint
The Chemult Community College NERO Checkpoint is a Highway 97 checkpoint at the college's old refugee camp. It pays Diamond Lake and holds an injector, and the college also has an infestation and a 125-Swarmer Horde.