Here's the problem:

You're willing to experiment, and your handle on the subject is "a hard disk recorder of some kind." You're wrong, by the way - if you wanted to do it on the cheap, you could effectively run a boom mic into an iPhone. But that requires knowing a lot more about what's going on than we've been told and there are many, many ways to screw it up between here and there.

I'll say this: a non-negligible portion of my income in 2010 was from indie pikers who thought they could do it themselves and then ended up needing to reshoot because, well, they were wrong. Which effectively doubles your shooting days and, therefore, the budget.

When someone says "I wanna learn about mixing audio" I have a very different response. When someone says "I'm stuck doing this somebody keep me from totally screwing it up" I have a very different response.

But when someone says "help me spend not nearly enough on gear I don't understand to do a task I'd rather not do" the answer will always be "find someone who WANTS to do it and pay them what they ask for."