Just a few comments from someone who is also working on a golf game, albeit one that is very different in style and implementation!
And if you use one single big texture for the terrain, you might create a down-scaled copy in a bank that will hold a material code for each 4*4 or whatever pixels. So you can check for diffrent materials (maybe color based) without to slowly peek in the texture all the time.
If it's any help, that's what I am doing in my golf game. I have what I call a "colourmap" which has the areas of the course (e.g. green, fairway, bunker, etc.) blocked out on it in colours (e.g. red, white, blue, etc.) and I translate the x and z co-ordinates of the ball on the terrain to an x,y co-ordinates on the colourmap and check the colour of the pixel there. Then I know whether the ball is on the green, in the rough, etc.
Using the mouse to determine the swing is the way to go. Relative to a golf swing it just makes sense.
Ah, I've gone for the 3-click system for my game as I am an old school Leaderboard player, none of this fancy mouseswing stuff thanks!
I'm trying to keep the game simple and true to golf so I'm so only looking at a First Person view with some fancy camera work -- no player model.
That's interesting! I've gone for 3rd person with golfer models, so I'll be curious to see how well this first person works, would have saved me some £££'s on models!! ;)
Good luck with it all...
Cheers,
Ryan