There's no specific emulator for the HOMM series, from what I can tell. Most people are using DOSBox, and if you have access to the DOS edition of the game, it's worth setting up and using. There are many older games that run under DOSBox, and it's pretty easy to set up and maintain compared to a virtual machine or similar solution. DOSBox rates this game as "playable" and you can use the user reports on that page to avoid any common errors and understand what might not work properly.
If you have the Professional, Ultimate, or Enterprise editions of Windows 7, Microsoft Support suggests using Windows XP mode to run HOMM2. This is pretty similar to your VirtualBox solution, but if you've got it built into the OS, you might as well use this as a shortcut.
Sometimes editing the compatibility settings of an application can get it to run in newer Windows versions than the one it was designed for, but given that the game is so old, it's unlikely to work. Given its low time/effort investment, its still worth a shot, though.