I've never tried the DOS version of Gemulator, but I think it needed physical ROMS on a special ISA card in order to run?
A very capable (but old) emulator for DOS is PacifiST - it's actually my favourite ST emulator, but development stopped and it was never released as open source
It does run most things though. I did set up an old Pentium 1 laptop and wrote a very rudimentary menu in Autoexec.bat where i could select different TOS/Machine setups at boot time. As close as I could get to owning a ST Book or STacy