I have been using Amaco Sculptamold modeling compound when trying to do track impressions. I make a layer of the compound and just run the wheels in it or press the tracks into it and have not had much problems. You have to do the compound a little dryer than the instructions or you are right that it will not give the right impression. I use the compound also to do my dirt, mud, etc., even molding rocks. I use it directly over a styrofoam base that is roughly the shape that I want. I sometimes use the kits parts if I don't have spares, before painting, then wash them off if necessary.

Tracked vehicles tear hell out of everything except the hardest ground, like dirt roads that haven't seen rain lately, and curb the dirt into a flour-like surface, upon which a guy who's just walking will raise a cloud of dust, lol... They don't leave impressions crossing a grassy field, they leave ruts... Tear it up, don't bother with track impressions,...

Wheels- depends on the surface again... But I use kit wheels too... On muddy roads, they clog the treads with mud, too... You wind up with "slicks" due to the mud... So it didn't matter if the kit wheels clogged...

Always used the tracks myself and then washed the plaster whatever off the model. When I dries I'll use a cutter ball thingee (don't know what you call it) in the motor tool or a screwdriver to 'enhance' them if needed. That's interesting Sgt Fury, guess I really don't have to do all that work.

I have a few old tires off a Greyhound armoured car and a Jeep I use sometimes for vehicle wheel impressions.

I've fallen into track-ruts moving around at night in grassy areas, lol... With the dirt banked up from turning, they can get two feet deep..

Rock, was that on a training area.

Awesome. No need to get crazy with it, then. I'll just dig it up. Good excuse to weather the model a bit more with some sloppy tracks.  Thanks, guys.

Chris