I find the USGS maps to be the best for finding counties. Other maps, and particularly Google Maps, either don’t have the county lines/names or don’t make it very clear what the county names are.
The LoTW server allows files to be processed that have multiple station locations. The TQSL application does not do this. The published API for creating files to be submitted to LoTW does not have any high level routines for doing this. Many years ago I managed to work out how to make this happen with the lower level routines.
I have written my own logging program that has my station location as well as the other stations information. It can automatically generate files for submital to LoTW that have multiple station locations. I have been submitting such files to LoTW for years and they are processed just fine. The most different station locations I have submitted in one file is seven, if I remember correctly.
You still have to go through the effort of figuring out the county, grid, and zones of course and entering them in your logging program.
Encourage whoever is writing your logging software to add more and better functionality.