Jawohl!
I’m thrilled to see that you are progressing as a mapper. Isn’t mapping fun!
About vehicles: I have never done that (because I think it takes too much time). But, I would use the original goldrush.map, if I was going to do it. Just load up the goldrush.map in your editor and copy all entities for the tank (or the truck). And paste them into a small map (just to test it - to see that it actually works). You also need to copy the relevant script (from the original goldrush.script file), to make a new script for your test map.
Or, you could write a private message to another mapper. A mapper who has used a vehicle in a map. Just ask: “Do you have a vehicle-prefab, and can I have it, please?”. I do not have such a prefab, but perhaps someone else.
Good luck!
// Loffy