Thanks for the positive comments guys!
I do use a plane with reflection mapping for the water, and a semi-transparent (using SET ALPHA MAPPING ON) disk above it with an animated water texture for that effect. It's like a poor man's pixel shader.
The "cache missed" implies exactly what it says - there was a request to the object cache for a scenery object but none were available because they were all already in use. The scenery objects get hidden and reused as they go out of view range.
The fps isn't great but I only have a P3 800 with a Radeon 8500. The reflection effect drops the fps by about 5 for me when it's turned on.
There is collision for the large trees (ie based on the matrix GET GROUND HEIGHT command, because the large trees are just the matrix streched), but there is no collision on the larger scenery objects like the rocks and fallen trees. I'm working on sliding and climbing collision for these.
Hope that answers all the questions.
PS.. The link to the new RGT forum is:
http://www.dannywartnaby.co.uk/rgt