
I'm not claiming that my theories are factual. Only that some of your texture programming is not what I have come to understand as being "the norm". I'm most curious if the methods you used in Chambers were common practice and I've just never heard of them, or if you may be creating a problem programming them the way you do. I'll elaborate, and perhaps some of these old designers might help to clarify.
For 1, you are creating seam blends that take up hundreds of yards of ground that is made up of bunkers and ponds and other texture. As odd as it sounds, you might build a tee box right smack in the middle of a seam blend. I find it amazing that it actually works. I don't recall anyone ever doing it that way. I don't really understand how you get the path mappings to calculate. I think of a SB as a singe path that is designed to blend 2 textures together. Generally that path is only one face wide. In other words, two outer edges with no other edges separating them other than the cross edges that connect them together. Think of a cart path or a sidewalk with cracks. I've never seen a seam blend that makes up large parts of the course with bunkers or tee boxes in it.
While I was working on Chambers, I would try to view from the TOP with the textures turned on, and the APCD would go into an intermittent stall as if was trying to read something but not completing the task. The little Win7 cursor would turn into a little circle and spin for about 30 seconds, and then release, and then go right back to spinning again. It would do this over and over and over, and never seem to complete what it was trying to do until I pressed CTRL F. (toggle off textures view) Then, I would wait a bit, and eventually the command would take effect during one of the pauses, and when the textures went off, the APCD would free up and function normal. If I worked down near the ground, I could turn the textures back on, but as I starting backing away and taking in more of the plot, it would start having trouble and stalling out again. Obviously it was having a problem rendering something when the texture views were enabled.
Here are some of the things that I found that didn't seem right to me.
When I tried to do a V&S, I was getting a message that there was an error in path mapping 104 and that it couldn't calculate it. I sent you a picture of that path mapping, which is a seam blend path. I'll attach it for others to see and comment on.
Here is the SEAM BLEND path that was kicking out errors. Notice that this path takes in a really huge area. Plus it's very oddly shaped. There's also a round tee box right in the center of it in one area. To fix it I kept breaking it into individual sections until I narrowed it down to a smaller area. I carefully went over the edges and flipped a lot of them in the areas where large groups of them join together. This may not make sense, but I would think of the path mapping as a stream of water, and I would try to turn the edges in ways that would make the water flow with the least resistance. After I went over that area and did that, the error went away. The bottom picture is the area that was causing the errors.
Note the "U Wrap" and the "V Wrap" settings. In most cases if you are working with default planar settings (which you are) the V Wrap should be set at around 10. All of yours that I looked at were set to 1, as if you never attempted to set them. Also, many of the ones that I fixed needed to have the textures "Flipped".
When I looked at the multiples, they all had the correct PATH mapping in them, and the 2 textures were always set to "default".
Another issue is that you have the same hi-def 1024x1024 long grass texture entered into all 3 Texture Previews in the "Near, Medium and Far" menu which is causing the long grass texture views to constantly fight each other as you move around on the plot at various altitudes. I'm not 100 percent certain of this, but there's a possibility that the seam blended textures that are using that long grass texture, are also constantly fighting to render the seam blends at the different altitudes. I'm pretty sure those seam blended textures get their properties straight from the stand-alone grass texture that you assign to it. I suspect with that constant calculating going on with those huge odd shaped seam blend path mappings, plus the 3 high-res top views, plus the odd settings in the V Wrap box could possibly be making the APCD try to calculate more than it's tiny brain can keep up with.

Here's my conclusion...
Due to the way these seam blend paths are designed and programmed, I believe that they are stalling the APCD while trying to render them when the textures are turned on. ESPECIALLY when you back away and take more of them in at the same time. The closer you get to the ground, the more it frees up the rendering speed.
I understand why you are using the 3 same size hi-res textures for the long grass. It greatly magnifies the textures and gives it a really cool and realistic view as you back away. Plus it helps to eliminate the irritating tiling effect. I'm waiting to see how the Links game deals with it when you try and put it to use during a round of golf.
Also, I love the way those seam blends look. That's some really impressive work in such a short time. I'm baffled how you can do that.


Anyway, lets see what others think of these findings.
Cheers

Dan