I agree there is no such thing as too much detail, at least not in theory... It adds interest to a scene and if done correctly it makes it more realistic.
On the other hand, you have to be selective about how much detail you commit to. If one of your scenes is highly detailed, visitors will expect the same level of detail in others. Consider that if you're working in a room the size of a basketball court. As other have mentioned, details can quickly add up.
For example, ground foam for grass looks great, but since they sell it in tiny bags with not so tiny prices, better do some math and figure out how much flocking those 40 acre fields will cost.
The same logic applies to other details. Consider the cost, in time and dollars, that a certain level of detail will exact.
I'd suggest picking a moderate level of detail at first, you can always go back and add more.