Well, my wife and I have been to three of the four reunions (missed the very first one). The reunions are really a whole different affair.
The run for 3-4 days. There are lighthouse tours, auctions of some very unique lighthouse stuff, and lots of fun with fellow lighthouse lovers.

For the Mackinaw Island reunion, we had boat tours that took us out onto Lake Michigan and Lake Huron. Harry Hine held lectures on the process of creating a Harbour Light replica and if fact, created the Cheboygan Crib replica at the reunion. Anyone that wanted to could actually scuplt a SMALL pice of the replica. The certificate for the replica lists the name of each person who put there hand to the sculpture.
They had one of their sculpturers and one of their painters there as well. The painter even touched up the paint sample of St. George Reef I won that had a couple of small chips in the base. You cannot even tell it had been out of its box now. If you have never been to one, it is hard to descibe just how much fun and exciting it can be. We are already preparing to set money aside to attend the next reunion wherever it is.

We have never tried to attend a regional because the cost vs return was never there for us. The Regionals are usually one day affairs. So for us to fly from Colorado to attend a one day get-together does not work. And there has never been one that synced up with our other travel plans.

The first three lighthouse reunions were heavily subsidized by Harbour Lights. The last reunion on Mackinaw Island was not subsidized by Harbour Lights. It had to break even on its own, which is why the cost was higher. In the current economic conditions, I would expect the same thing to be true for the next reunion.

I don't believe there were 529 people at Mackinaw because people could order more than one of the Cheboygan Crib piece. The reunion at Baltimore had over 700.

The cost per person depends alot on the number of people they can fit into the chosen venue. The tradeoff is the more people you have, the less personal time you can get with the Youngers, etc. The cost of each of the past reunions has been all inclusive once you were there. Travel costs to and from were your responibility. My wife and I have continually been able to get resonable airfare the past two years. Add-ons tothe reunion like additional lighthouse tours, etc are extra if you elect to do them. The hotels involved have offered the special room rate for the reunion to those wishing to stay extra days. Dave H. can correct me here if I have misstated anything as he put together The last reunion.

Will a reunion be inexpensive? Probably not. Is it worth it? That depends on each individual.
Will they do things from past reunions at this one. One never knows, but I hope they have a painter and sculpture there and Harry makes a lighthouse. That ws a high, high point of the Mackinaw reunion. From our experience, a reunion event is one of the best vacation experiences we have ever had. The only thing that still tops a reunion was our honeymoon.

(Boy, that is my longest post ever. Sorry for being long-winded folks.)