Replace text, AppleScriptt

I am working on a large .txt document that I am trying to clean up. I have some places in the text that I would like to remove some hard returns. I know I can use find/replace to do this, but I don't want to do it to the entire document.

What I was thinking was an AppleScript that would copy selected text, run the find/replace on that selected text, and then literally replace that text with the modified text.

I have been doing it like this:
* Highlight the text in question
* Copy that text and paste into 'Stickies'
* Run find/replace on the text to remove the hard returns
* Copy the newly modified text from Stickies and paste back into the original document

There has got to be a faster method. Can anyone help me with a script that I can assign to a keystroke to do the above? This has prompted me to start looking into AppleScript, but I have no experience with it. I do have some experience with AutoHotKey for Windows. That is/was awesome. If I was using Windows (or owned a Windows machine) at this point, I would have it done already. I have moved away from Windows, however, and so having to dive into Apple even more. Which has been great.

Thanks for allowing the rambling.