Extract Large No of Pages from Web Site & Create New Site

Hi, We are buying an existing website but not the server it's hosted on. We need to extract the existing pages by crawling the site. We then need to create a new site from those pages. I'm not sure if we want to use a CMS like Joomla or just go for HTML/CSS. The other complexity is that this is an accommodation site that also has sub pages for the accommodation owners where they can log in & update their pages. We'll definitely need a CMS for these pages but it needs to be one that's easy to use. Everything needs to be search engine friendly. I can provide the name of the site upon request. Lee. & re-creating them on another web server. The content is currently dynamically generated in a proprietary CMS & database. There are about 5,000 pages. In the current site some of the data can be updated