oh no =*( that happens to a lot of people... when i did my perfect town and helped the people i did, i always went across the first top of the town making the acres 16 spaces across the map - west to east. after i got finished with that i recounted them to make absolutely sure they were all 16 wide, then did the same going down to the beach.
just so you know though, the last acre, the one that ends with the beach, will be like 2 or 3 squares "short" sometimes because the shore goes south further in some parts and the sides where the town wall borders the town may be one of the shorter parts of the shore if that makes sense. hope this helps and good luck. =*(
try not to let it piss you off too much, lol. it's worth it. <3
yeah, when i came to rivers i just began counting from the other side of the town. the rivers (assuming they aren't turning in any way) count for 4 spots, and the top part of the river, the little pond the waterfall makes spilling into your town, counts as 8 if i recall correctly. i could be wrong though - would need to double check that. i haven't done this in a long while, lol.