Unfortunately, the season is over in your area as far as Hobie regattas are concerned. So . . . start planning to attend some next year. Join the Hobie Class Association (
http://www.hcana.hobieclass.com, join at
http://www.hcanamembers.com) and you'll start getting the class magazine, the
HOTLINE. It will have the regatta schedule for your area (Division 4). There's a significant concentration of races in the Seattle area, and if you're willing to travel a bit more, in northern California.
Over the winter, get a book like Dave Perry's
Understanding the Racing Rules of Sailing (You might want to wait for the new version which covers the 2013-2016 rule book which was just released this week.)
Another book to read is Rick White's Catamaran Racing for the '90s (yeah, it's 20+ years old now, but it's still good).
The first year you race, sign up for "B" fleet and you'll race against others of similar ability (although you'll probably start with the "A" fleeters). You won't need a new boat . . . yet.
Once you get proficient at getting around the course and gain more confidence with the right of way rules in boat-on-boat situations - and you start doing better in races - that's when it will be time for a new boat. A '70s boat will not be competitive against newer boats. You don't have to get a brand new one at first - a "hand-me-down" from an A-fleet sailor will work just fine. Something newer than 1995, but it's better to have something from the 2000s.
There's no qualification system for regional championships or North American Championships. Just show up with your boat and race. Easier said than done when the event is on the other side of the continent. However, there's usually a couple of fanatics that'll be driving - and willing to haul a multiple stack trailer for a fee (or gas/driving time if you're going along for the ride).
The best part about regattas is not the racing - it's the one-on-one help you get from expert racers on setting up, tuning and sailing your boat. That part of the event is
free. All you have to do is ask. Before you know it, your boat will be in the middle of a tuning seminar.
In the past, there has been a qualification system for the world championships. The boats are provided by Hobie Cat (brand new) and there's a limited number, so there's a limited number of competitors. Each region (like North America) is allocated a certain number of positions. Those positions are filled (via a mathematical formula) by a combination of your results in Hobie Points Regattas and your finishing position in the most current North American Championships.
However, there are always a number of "open" positions - usually 25 or so. In the past, there's been a two-day "qualification" regatta held at the worlds venue for anyone who wants to try and qualify for the open world championship.
Unfortunately, there's no Hobie 16 worlds on the schedule . . . yet. There's been a couple of proposals, but nothing has come quite to fruition. It will happen in the near future, and there will be lots of notice - usually about a year. Keep practicing!