Hi LuaMarketing! Great question and we get asked this a lot from clients/potential clients who have multi-locations. We are actually in the process of rolling out pages to target surrounding cities within a 15 min drive to try to rank for their less competitive markets.
To break apart my response, let's approach this from PPC and SEO.
For PPC efforts, creating landing pages is super effective for your user to get the info specifically what they were searching for, immediately (this stands true for SEO, but I'll get to that). PPC landing pages are generally less text heavy and more focused on CTA's, forms, phone numbers and the like, so having them not indexed in your meta data is helpful and recommended. As noted above, tons of companies large and small do this.
For SEO efforts, always keep in mind not to over-optimize the page as well as making sure it is a part of some internal link so the spiders can find it, crawl it, index it for the SE to rank it. Your content needs to be 100% original, readable to the visitor (Google is basically becoming more and more like a human reader) and relevant to what the searcher entered to make that page display as a result. The other critical component will be to build links to those pages through ethical, non-spammy link building tactics. There are plenty of websites which do not have all of their inner pages listed in the main navigation, nav bar drop downs, footer section... rather, they are embedded appropriately within the inner pages body content or within blog article content. It is certainly doable, however, if you think what you are implementing may be spammy, you just may be right. Follow the best SEO guidelines and practices and keep asking great questions like this and you will get the community behind you to help you grow your sites.
Hope this was helpful! Cheers - Patrick