I can't really help as much with your question as I'm trying to get into freelancing myself and technically also "a college guy". Hopefully, the two Syntax episodes below help some.
Personally, I feel that the freelance money is more centered around CMS-based setups for clients (Wordpress, Drupal, and etc). I think your fourth bullet point makes the most sense with this. There are NodeJS based CMSs out there but they aren't as popular and are harder to sell to clients than something that is more of a staple and widely-known like Wordpress.
It would also depend on who you are freelancing for. If you're freelancing for a small business owner/a small client, you'll probably be writing code within a CMS so they can edit things themselves. If you're freelancing for a bigger/tech-focused client like Twitter/Facebook you'll probably be coding an actual application from scratch.
I'm talking out of my butt though, someone with ACTUAL experience will give you better advice.
Here's a freelance calculator that might be helpful:
Aforementioned podcast links:
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