Use a VM or a DOS emulator/layer to play old games on modern platforms?
Depending on exactly what game you want to run, the easiest (and most common solution) is DOSBox, as you mentioned. Some games have issues with emulation - you may have to Google issues you run into now and again (e.g. setting clock speed for games running too fast, etc.).
If you wanted to, you could certainly set up a VM running DOS or Windows 95/98 and play things that way. As far as which OS you use, that's more of a comfort decision - whatever will get you up and running the fastest.