HI Wendy 
If you select the main group of “Vegetation” and make it invisible,. then the scene is much easier to work with.
just remember to make it visible again when you’re ready to render
For the motion path ,...
You can use the little Grid options tool on the side tool-bar, to select either the vertical plane’s , which will restrict the motion to Up/Down,/left right, and up,down / front,back, or the horizontal plane for left right / front back
it’s also useful to switch to the Quad vies, so you can see the front, top, left and camera views when you’re moving the motion path.

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