The next step

After the initial glut of input from beta readers slowed, it was decision time. How do I get my story into the most hands?
A few years ago, three options existed: 1. Get an agent, and be prepared to split profits but get a possible 'in' at otherwise closed publishing houses; 2. Send it to (often smaller) publishers that take unagented material and hope for the best; 3. Self-publish at your own expense and figure out how to sell the copies you've paid for.
The last few years have brought a number of changes to the publishing industry, and like the music industry, the fallout is huge. Independent booksellers have gone out of business in droves. Even the big chains are struggling, trying to compete with online convenience. These changes add options: 4. Print on demand publishing, and 5. electronic publishing. Probably other options exist too, but my head is reeling with just these.
As a first time author, I have no following, no marketing platform, no network within the industry. If I took option 3,4, or 5, how would I get a potential reader interested in purchasing the book?
Since my book is aimed at Middle-grade and Young Adult audiences, I decided to start with the tried and true. Traditional publishers still have the inside track in the school and library markets, and I think that's where most of my sales will be generated. So, this week I sent out queries and the first 10 pages of the manuscript to 4 different traditional publishers. They all have a 'we'll let you know if we're interested in 3-5 months. If you don't hear from us, we've thrown it out' approach.
So now I wait.