search bar for properties with start and end date

I need a search bar with start and end date for the website (like http://www.housetrip.com) I am building now.

When the user is pressing the Search button that should look and see if there are any available properties for the date specified and show them, I guess the next page will be a loop page showing what’s available.

Please give me an advice, how hard is this to implement? Is there any helpful plugin I can download and eventually customise?

I really need some feedback about this. Not mentioning the booking system I will be using for these properties is keepmebooked which stays in an iframe on the website, thing which I guess hurts SEO big time, isn’t it?

Thank you.