After messing around with it a bit more today, there's more problems. I guess I wasn't thinking because of how late it was, but when the game loads a new day, a couple disruptions happen...
The first is that anything that has the "Growing" tag will actually grow. I just assumed that, being placed manually, it wouldn't actually proceed, but it does. This means that after a day, Bamboo (Growing 2) ends up being a full one, and sticks out. The second is that, for unknown reason, the rocks disappear. I don't know why this happens. This seems to be the case whenever a rock is placed in the river. Bushes, however, are short enough that they won't interfere with fishing and don't off themselves. The only problem is that they don't really look... amazing. They don't stick out like crazy, but they don't really look right.
If anybody has some ideas, post 'em. I don't know of any other place-able objects that have collisions, so we might be stuck with bushes. It doesn't look terrible, but it isn't the most preferable one, either.
It should be noted that I haven't tested the whole "rock-in-river" in a fresh town. My current testing town had no rocks as of placing, so that might be interfering with something...? I tried placing a ton of other rocks, but they all went away, too.
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Also, if anybody is good at looping music, pls halp. I'm disgustingly bad at it, so I'm having trouble getting anything done regarding that portion of the mod. I have all the files, conversion methods, etc. but looping is killing me ;w;