If this is about shows, stages/rooms first ask yourself how much do you really want to haul. You may already have the fastest, easiest.
Or if packing a mixer of any size and sort, all cabling, and 1 to 2 powered PA speaks along with the other gear isn't a bother then go do that voodoo.
I think it's easier to go amplifier for all in one ease. Then when possible feed a mono or stereo out from that Roland amp to the house/stage monitors if you needed more.
* google or youtube, etc will answer all your mixer and preamp questions.