If I understand correctly what you want, you want a ‘page in a page’. This is very easy. Just use this plugin. It has support for widgets and shortcodes. Especially the shortcodes will be interesting for you.
The plugin description repeats that it’s mission is to
bring your Facebook posts and Twitter feeds to your blog.
You can ignore that, you should be able to use it for other purposes too.
The plugin has good reviews. 3 with 5 stars and 1 with 2 stars.
The minimum WordPress version needed is 3.0.1, but it doesn’t work with versions after 3.8.3. If you are still using an outdated version you should really consider updating.
Good luck!