The optimal path is to set up multiple streams of income for a site from the start, so you have money coming from source B and C if A is stopped. So start from the most clicked adsense keywords, then find or create CB or other digital products that fit that niche, and also intersections with physical products (from Amazon or eBay, etc). Ultimately you have 3-4 income centers per site, so if Adsense fails you can rely on the other sources.