Below is a diagram of the total cost (in coins) to remove all obstacles from each expansion plot that I had notes on. The cost for the expansion itself is dependent on how many expansions you have made already (except the plots with the Treent of Life and Hareon). The idea is that once you have expanded to the mine, you have a choice as to where to expand. This is to help you determine the hidden cost of each expansion. Those of us who started playing when the game was new had much less choice in the matter. We had only the first island, then the lower ice island, then the upper ice island to choose from. But those who started later can save a TN of time and a TON of coins by putting off those islands other than the first 5 squares of the lower to get the lightning leopard, which you really, really need.
My recommendation for the order in which to expand:
- Once the mine has been reached, expand to the 3 squares in a line from the mine going southwest. You need cheap space fast to earn income.
- Then go to the first blue island. It's cheaper than the bottom row on the main island, and if you expand up the left side and across the top, you get the Lightning Leopard - getting that lightning element ASAP is crucial.
- Then open up all of the first purple island (with the Hareon).
- Then finish off the bottom of the island we start off on.
- Then the second green island. I recommend going up the right side of it to the Treent of Life. That way, when you have the 10 million to open that plot, you actually can.
- Then fill in the other half of that island and the other half of the first blue island as suits you, and/or in order from least to most expensive.
- Don't bother with the top blue island at all until EVERYTHING else has been opened. And be thankful you have the 26 plots on the second green and both purple islands available to you before having to resort to the absolute horror of this island that those of us who were around from the beginning had no choice but to resort to because we didn't have those 26 plots. They opened after we spent weeks and millions per single plot and reached the 70 runes expansion phase. It sux to be us. Be very glad you can expand for much less than half the price we had, and can clear most obstacles in 20 minutes not 33 hours. The top blue island should be avoided until EVERYTHING else has been opened.
That said, feel free to forge your own path! My recommendations are just that. If you like filling out one island before starting another, go for it! But go for it with the knowledge of what its hidden costs are.