Plugin/Custom code: custom field(s) and post order

I have been dabbling in WP for a year or so with the intent to roll it out for a non-profit professional organization for whom I currently administer the website. The current site is coded in HTML, PHP, and CSS and is cumbersome to update (all by text editor). One thing that has kept me from doing it so far is how I need the posts organized.

Almost all of our posts are related to a specific lecture event that we’re hosting. For each event, the home page provides date, time, location, cost, and short description and links to the full page with all the details (abstract and speaker bio) and the Google Form through which I’m handling online registration.

It seems that WP is ideal for this and will help with grouping posts by year and topic and so forth except for the sort order imposed by The Loop. I would like a custom field “Event Date” used for sorting (rather than the date it was last updated or posted) and I would like the sort order to be: 1. the next event, 2. the upcoming events (from coming-soon to out-in-the-future), 3. the events that have already happened for the year (from most-recent to least-recent). I have not yet found anything like this in my searching but there are a lot of sites and a lot of plugins to search!

In an ideal world, I’d be able to find a plugin that would do this, handle my online registration, and link to our PayPal payment option. But that might be a bit more than I handle on my first WP roll out!