Ok, I will attempt to help you out, as I have a pretty decent method for making these types of grassy plain areas.
The 1st thing you want to look at are the PBR grass textures by Johnnyc1. He is a VERY prolific texture creator, so don't be daunted by the sheer numbers of textures he has on the DLS.
Look for any and all textures with grass in the title, download all of them. You will likely not use them all, but as you build your route, you'll want to have them all available to experiment with.
You will also want to look at the soil, ground and mixed sets that he has on the DLS, as some of those can be used in transition areas near the rails, along cuts, creeks and any hills you might have.
If you have any water features or open ground that might be muddy, there are also mud sets that work really well.
The grass splines that are available on the DLS are a real mixed bag of quality, and age. Here again, you'll want to download alot of different splines, to have a good library to choose from when laying them down.
Method-wise, I will pick an area of empty based board, then build patches of blended textures in large areas, that you can then use the copy/paste tools to apply along the rail lines.
Texture out from the rails for about a quarter of a baseboard worth of grid spaces, using the rotate tool as you paste to further blend these large texture patches.
They do not need to look perfectly seamless, as any differences will be hidden by the grass splines once you start laying those down. Keep the scale at it's lowest near the rail lines, and use the rotate tool alot as you plop texture, to avoid patterning in the blend work, and give better color blends with the grass splines you will be laying down. This matters less the further away from the rails you work as most splines will start to lose sharpness and detail the further away from the camera they are.
Now comes the annoying part. Going through all of the grass splines and laying them down on top of your pasted textures. Due to the methods used to initially create some of the splines, you will find that some have an annoying two sided shading problem, dark on one, light on the other, and this all depends on what direction you lay them down. You will want to lay them down so they are tangent to your rails, so the ingame camera from the train will see the best side as you run your session(s). Some splines also have a edge flicker due to faulty mip-mapping, which I think can be fixed, with some photoshop work, but not really worth the time to do. Those assets really need to be reworked/exported correctly.
You can lay some at angles to the rail lines, but not too acute, as then you see the obvious billboard effect of each spline that way. Mix grass colors and heights, building irregular patches to resemble your screenshots from your Montana thread. On routes with rail work that has a narrow corridor of site restricting scenery along the rails, laying the splines in a near parallel fashion works better, as you will likely have the game camera focused directly forward or backward most of the time. Take into consideration how YOU will drive your route when choosing how to lay your splines, i.e. in-cab, Chase or line-side camera with placed camera assets.
Find and download clam1952's CL Bush sets, and plop clumps of those (again, build copy/paste patches and apply) all over to simulate the random low level bushes found on Montana plains. Keep the bush heights low, embedding part of each bush into the ground.
I guarantee you will not get a prefect result, as the main issue is the quality of what we have available on the DLS isn't good enough for really photo-realistic scenery like other games or sims you may have seen or played in.
Also, when you're in a train, running a session, the splines will still have a tendency to draw themselves in chunks as you drive along, unless you have a really beefy comp setup with very fast draw capabilities.
You can get some very pleasing looking grass fields with these methods, but you will have to be satisfied with what's available.
Rico
