Hi Chris,
It's really important to understand that Local Search is city-based, not state-based. Local SEO revolves around optimizing core pages of the website and the footer with your complete NAP (name, address, phone number) of your physical location, building a Google+ Local page for that city of location, building citations on various directories for that city of location and earning reviews on them, plus any links and social mentions you can earn.
For any city in which you serve but are not physically located, it's a best practice to build city landing pages on the website with totally unique content on them. These will not typically achieve local pack rankings, because there is no physical address tied to them, but they can achieve organic rankings for searches pertaining to these other cities.
So, if you are taking a Local SEO approach to your marketing, and let's say you're physically located in Denver, then your core pages and NAP and citations and reviews will all need to reflect the Denver location. Your title tags and content on these pages will be most geared toward Denver. Your city landings pages for cities where you aren't physically located can then reflect other cities like Boulder, Aspen, Colorado Springs, etc.
Typically, even if you serve statewide, you're not going to build a landing page for every single city in the state. I mean ... technically, you could do this, but it would be vast project. So, in general, what you'd want to do is to identify maybe 10 major cities in which you serve and build a unique landing page for each.
Then, I would recommend setting up a blog on your website and when you build a barn in another city, writing a blog post about this. If you build 50 barns a year, that's 50 blog posts and 50 chances for Google to see that you've got unique content on the website featuring your work in this variety of cities. You can add to the static city landing pages over time, too, and you can be sure that the homepage and contact page of the website reflects that you will travel anywhere within the state of Colorado to serve, but tackling the whole state at once is likely to be too big of an SEO project for any business. Taking the work in steps and stages will enable you to build great content that is highly relevant to people searching from the various cities in Colorado for the services you provide.
Hope this helps!