Here's an "unwelcome twist" to expanding to the new plots: check out the below three screenshots of the first expansion I made there. First there was the normal 1,000,000 coins cost for the expansion itself, but then to my unpleasant surprise, there were 5 pieces of foliage to clear out, and all but one are expensive!
There are 3 Obsidian Deposits (costing 400,000 each), 1 Basalt Boulder (500,000) and 1 Smoking Shrub (25,000). I really hate it that when we can finally expand, we first have to go through a long timer (18 or 19 hours for me) and then this. The total cost just for clearing the foliage away on that spot is 1,725,000 coins. Add to that the expansion cost (1,000,000 for me) and that's no picknick.
The only good news is that the foliage clearing times on this spot all are 20 minutes as opposed to the 33 hours (!) of the upper blue shelf.
In itself I don't mind it so much if something costs a decent amount of coins, but as I've been doing back-to-back Charm Cherries plantings through the days, and Nexus Nuts overnight, my funds are now depleted and I couldn't directly buy a Treasure Trove to let it start building overnight. My hourly earning rate is just over 100K and the top earner, the Quartz Quetzalcoatl has been in the den all of the past week and is in the flower now. I'm going to have to take a small break from harvesting now, so tomorrow morning I should have enough cash to start the construction of a Treasure Trove.
Can anyone who has already reached the Solar Bear tell me if the other plots in those regions have about equally bad costs?