Mepis, if it works like all the other live-cd distributions out there, should recognize all your devices that it has drivers loaded for. Try out (usb-devices might have to be plugged in after it's booted, to make sure it gets them, if they don't get up when you plug them before booting) and if it doesn't recognize something, either try to get your hands on it manually (that means mounting if it's a harddisk, cd, dvd or some other media) or giving some extra kernel parametres. But yes, in most cases you only need to boot and plug the devices in and see what happens
