Bid by county, because Douglas and Adams do not shop for the same pool
One budget spread across the Front Range hides the fact that you are buying two or three different customers at two or three different prices.
Split campaigns geographically before you split them any other way. Denver County, Jefferson, Arapahoe, Adams, Douglas and Boulder produce different lot sizes, different budgets and different drive times from your yard.
Drive time is a cost, not a detail. A crew sitting on I-25 to reach Castle Rock is a real expense that never appears in the ad platform. Bid accordingly rather than pretending a click is a click.
Give each geography its own budget and its own reporting. Averaging Highlands Ranch and Thornton together produces a metro cost per lead that describes nobody.
Then split by job. New construction, renovation and equipment work have different values, different close rates and different seasons. Sharing one budget means the cheapest clicks eat the most valuable campaign.