Drove the entirety of Citrus County Route 490 (largely at the suggestion that the northern construction of the Suncoast Parkway can be seen) today. There are some oddities on this route like a very unique US 19/98 junction sign, the Suncoast Parkway extension construction and apparent signage gap in Homosassa:
https://flic.kr/s/aHsmz9cwGT
Interesting CR 490 appears to end about a quarter mile short of the Yulee Sugar Mill Ruins at Mason Creek Road.
Well it seems FL 490 did at one point end at the Homosassa River but it appears to have been a later route extension. There doesn't appear to have ever been a FL 490A, the current County Route appears to be only a couple decades old:
https://surewhynotnow.blogspot.com/2019/01/citrus-county-route-490.html