In case you don’t have a copy of Command & Conquer laying around, I have some good news! The game was released for free a while ago and the good people at archive.org are hosting image files of the original CD-ROMs on their website.
Just grab the ISO files, mount them in your Dosbox and there you go 🙂
Ofcourse if you want modern support like higher resolutions and smooth multiplayer you can try OPENRA. I know this isn’t the real DOS experience, but i put it here just in case you guys want to try. http://www.openra.net