だいたい here is the straightforward adverb 'basically / roughly / in general,' no rhetorical edge. を marks 辺り as the path traversed — the を-of-path construction, used with motion verbs to mark the route or area covered. のが nominalizes the preceding clause as the subject. である is the formal written copula, slightly stiffer than です or だ. 基本的な uses the productive ~的 suffix to form a na-adjective.