There is quite a lot of land available is spotty areas. Most the safe zone have 8x8 spots here and there with a few 16x16s. Almost none of the land is open enough to join together multiple plots side by side unless you buy it from housing sales, etc. But daily there is someone wanting to sell this 24 or that 16 etc.
That said, there could be A LOT more land available if people were not so horrible at placement. There is a lot of spots where you coul dhave fit two 16 farms if the first guy would have aligned his to the border of the one to the immediate left or right rather than in the middle, which wont even allow an 8x8 on either side. Perhaps people do this on purpose to be a dick and hog for "future use" or because they dont want to be crowded with neighbors. This was always a gripe of mine with the Trion retail version as well. You can literally place your plot anywhere within the border of the zone. In whatever messed up configuration you want.
I sorely wish there was a forced "snap-to-grid" system when you place land so that my garden (and others) would line up next to the border of the last one placed or boundry of the zone where I cant take a 24 by 24 open area and place a 16 scarecrow in the middle. It would force me to snap it to one of the corners leaving 3 more adjacent 16s open