So, here are some updated pics of the progress to date.
This shot shows a portion of the fill and grading that was done. Over on the right hand side, from the edge of the dirt to the edge of the pond, we filled in probably 2 to 3 feet of dirt. This dirt work goes for about 600 feet from the front of the pavilion out to our access road and mostly covers the area of the utility ditch we had dug for our water and electric. Most of the rest isn't nearly as deep, ranging to as little as probably six inches. Our soil is so clayey and rocky from being strip fill that I had the excavator bring in a bunch of fairly clean dirt to put a decent growing layer on top of the existing soil.

This is another shot of the dirt work going out to the access road. That last picture is just off to the left of where this one starts by maybe 50 feet.

And here is a shot from up on our ridge looking down at it all a couple of months later. Got a decent grass base reestablished before the weather turned on us.
Here is the pavilion with roof sheeting finally installed - felt/tar paper on one side, the other side fully shingled. This is before the extension was poured and actually shows the old form for what was just going to be a 4' extension before we removed it and made the 8' extension.

And from the other side.

This view is from standing in front of the bathroom looking up and out the open end of the pavilion. It gives a pretty nice feel for the tongue in groove roof sheeting from the finished underside as well as the big beams that make up the frame of the pavilion.

This one shows the joint of the main beam in the peak of the roof. The original contractor had it braced with a piece of 2x4 and it sagged causing all kinds of issues. I had a local guy fabricate two 6x32 braces of 1/4" plate drilled with 8 holes. My buddy and I jacked the beam up to level then bolted the two braces together with grade 8 1/2" carriage bolts.

This one shows an intersection in the beam framework. The original guy didn't plan for these 3/16" brackets but I thought they would help stabilize the frame plus really enhance the overall rugged look of the finished product. When we bolted all of these in place we were amazed at how strong the whole structure became. It truly exceeded what we thought would happen. They are locked in by six 1/2" x 4" lag screws in each bracket. I still have six additional brackets to add because we ended up using some of the first batch in areas I hadn't thought about when planning. Those are being made now and should be ready to put in place within a few weeks, but they aren't critical to the stability of the overall structure at this point.

When spring rolls around, we'll pressure wash all of the wood and then add a clear stain that has a reddish tint to it on all the wood. The bathroom will be finished in T111 inside and out and it will also be stained. As well, the exposed vinyl siding at the closed end of the pavilion will be covered with T111, too, to match everything up. We'll also end up adding soffit and fascia along the faceboards to cover the screwups caused by the original contractor. I wanted to have that area left open, but he was so badly out of square that we ended up doing a lot of remediation with scabs on the ends of the rafters to get the faceboards straight and uniform. The soffit and fascia will help conceal all of that and will also serve to tie the pavilion to the original building more in a visual sense so it will look less like an afterthought.
I expect that we'll get back on it in a few weeks and get the one side of the roof finished up then start tackling the bathroom. More pictures as work progresses!