I am working on a project that is basically a site to list apartment for rent (similar to apartments.com or rent.com). We want to add a bunch of amenity pages, price pages, etc. Basically increasing the page count on the site and helping users be able to have more pages relevant to their searches and long tail phrases. So an example page would be Denver apartments with a pool would be one page and Seattle apartments under 900 would be another page etc.
By doing this we will take the site from about 14,000 pages or so to over 2 million by the time we add a list of amenities to every city in the US. My question is should I worry about time release on them? Meaning do you think we would get penalized for launching that many pages overnight or over the course of a week? How fast is too fast to increase the content on your site? The site about a year old and we are not trying to scam anything just looking to site functionality and page volume. Any advice?