The sentence in question: 文化１４年、西暦１８１７年の１２月２９日の午後２時ごろ、甲州街道沿いにある宿場町だった今の八王子市とその周辺の日野市や多摩市に、雷のようなごう音とともに隕石の雨が降り注ぎました。
My attempt at translation: "(??文化１４年??) around 29.12.1817, 2.p.m, in nowadays Hachioji City, which existed along Koshu Kaido and was an inntown, and in the surrounding Hinoshi and Tamashi, a thunderous roar like lightning thunder together with a rain of meteorites rained down incessantly."
I think 甲州街道沿いにある宿場町だった今の八王子市 and その周辺の日野市や多摩市 are both local adverbials, connected through と and made local by に. However, especially 甲州街道沿いにある宿場町だった今の八王子市 seems rather complex and Im not sure wether I resolved the attributes correctly.