Anyone who actually has real experience doing this would be ideal.
I suppose that would be me.
I apologize, but I'm having a difficult time not turning this into an angry ten page rant about the state of the industry. But since you don't actually care about any of that and just want to make some money on the side, I suggest you sign up with a third party provider like
elance and be prepared to engage in bidding wars against 300,000 other people who've also "got a wealth of experience, good skills, solid instincts, and a burning passion for anything proofreading- or editing-related" competing for the 20 or so jobs that are posted on a typical day.
Incidentally, "got" is past tense of "get." As in, "to receive." I believe the word you were looking for was present tense: "have." "I've got a wealth of experience" basically means "in the past I have come into the possession of a wealth of experience, independent of whether I continue to have that experience at the present time." Which is clearly not what you meant.
But don't let that stop you. These days, any stay at home mom and ESL Indian willing to work for $10/hr is more marketable than a guy with ten years of industry experience, who's worked in every step of the process from manually loading printers the size of trucks with crates of paper, to light proofreading, to formal substantive copy editing, to newspaper physical layout, to pre-print production, layout and formatting, to copy writing both with and without accompanying graphic design, to electronic formats and e-book conversion,...and who incidentally also wrote an in-house technical manual for a fortune 100 mortgage company, has his name attached to nine published novels, built the website for a publishing company and was a badged member of the press for almost two years.
Oh dear. It seems that the bitterness is creeping in again. That's obviously not helping you. I apologize. I'll try to reign it in.
Sure, you can work at home for peanuts. Everybody else is, so why not?
How long are the lines for these sorts of positions, on average (is it a very competitive market)?
For online bidding, 10-30 bids per project is common. Depends on the job requirements and pay. For something especially good, you might have 60+ competitors. For something not-so-good, you might only have three or four.If you mean real life jobs at brick and mortar locations where you physically go in and sit in an on-site office, it's 100 applicants per single position, and none of them are hired because the position is filled by a friend of a friend before the ad reaches circulation. And I do mean that literally. Very often when you see a job listing the position was filled before the listing was published. But HR policy requires that all jobs be posted, so they do.
In general, what do most paying companies/organizations look for when hiring a proofreader/editor? Years of prior or current service in a related job? College education? Solid resume? How long are the lines for these sorts of positions, on average (is it a very competitive market)?
Nobody cares. There just aren't enough jobs and too many people who want them. Even with my background, I've applied for staff positions at newspapers and magazines and I don't usually even get a form letter in reply. And in your case, talking about entry level proofreading positions...it's pretty much hopeless. It's too easy to submit a job to online middle-men like elance and amazon turk. If you're familiar with HTML, CSS and google analytics, know SEO basics and are willing to pretend that "must know wordpress" is an actual job skill rather than something that any idiot can pick up in an hour, you might be able to find some $10/hr work here and there on craigslist. But be prepared to respond to 20 ads for every ad that isn't a scam or an "unpaid internship."
I'm not necessarily looking into this as a full-time career
That's probably a wise decision.
tl;dr:
Go ahead and try elance. See if you like it. Just be prepared to do some fairly miserable low paying jobs to build up your reputation. Also be sure you understand how escrow works, don't work for free and don't be surprised if sometimes you submit bids to projects that never actually happen for no obvious reason. If you want to work online from the convenience of your home, work of that sort is available. But understand that you're competing for bottom dollar against other people who also have, as you phrased it, "got" an absurd amount of free time and just need something productive to do with it.