Linking off-site can help integrate your new website with other branches of your business, as well as provide references for other great local area information. However, external linking can have consequences when it comes to SEO value. It is crucial to review these concise best practices before you begin linking from your new website:

Adding a link to your real estate site (or any other site) to the main navigation is not ideal. If you absolutely must link off-site in your main navigation best practice is to have that link open in a new window so that the user doesn't leave the client's site. We have made this the default setting on all of our websites for your convenience.
Another thing to avoid is linking off-site on an area guide page. Many area guide pages give the impression that your site will provide content on recommended activities, restaurants, etc. That is quality content to have on your website that creates positive SEO value. Avoid linking to larger sites like the local Chamber of Commerce when possible. Linking to a local business can be ok if you have a page with content about that business and you want to send people their way, but is not great practice to link externally without any onsite content whatsoever.