The best level to make money on is actually level 15 of Rabbid Journey. Here, there are about 100+ coins as opposed to about 87 coins on the other level from the other post.
The easiest way I've found to do this is to purchase the Power-Ups that say "Win 8 coins for the price of 1" (has the gold bar icon, second from the left on the bottom row) and "Guide the rabbid where you want to" (has the black hole icon, last one on the bottom row).
Now, you might think: "But if I buy both of these items, I'm spending 480 coins!" That's exactly right! However, you won't have to navigate through the level with your jetpack. It took me about a minute to grab all of the coins, which gave me about a 320 boost to my coins on top of what I had. Sometimes you have to spend money to make money.
If you think you can manage without the black hole Power-Up, you can try it with just the coin bonus. You can also grab the Magnet Power-Up as well. But when you do it one of these ways, you spend much more time running around.
Anyways, that's what I found while going through this. If you have any questions or comments, please post below!