Complex sentence: Loomis is amazed the valley is radiation-free (a "meteorological enclave"); and, after Ann moves him into her house, he explains how to get gas manually for the tractor and begins planning a hydroelectric generator.
Split into simpler sentences: Loomis is amazed the valley is radiation-free (a "meteorological enclave"). After Ann moves him into her house, he explains how to get gas manually for the tractor and begins planning a hydroelectric generator.