Redmine is getting more and more popular and is therefore becoming a tool on which companies want to build their businesses. So, this certainly helps to obtain more and more options for easy installation of Redmine. I guess no one can now say that it's hard to establish a Redmine server.
The easiest way to establish a Redmine website is perhaps by using a dedicated Redmine hosting provider. The problem with this option, however, is that you are limited in the customization of your Redmine instance (for example, you won't be able to install custom plugins). Also, you will have to deal with the customizations of the hosting provider (which you may like though).
One of the oldest and best known Redmine hosting providers (on which even some of its core contributors now work) is https://plan.io/. Their customized Redmine comes with the agile board, contacts, the CRM and helpdesk functionality (plugins of http://www.redminecrm.com/), news renamed to blogs...