On my Ole Mirada, I can set valves so the water pump sucks out of a container, this can be fresh water or antifreeze.. I can also select if the pump sends the water through the plumbing (normal) or into the fresh tank to fill the tank.
You should be able to do something similar. If nothing else, dump the antifreeze into the fresh tank then pump it through your plumbing. (make sure to shut the fresh drain if you do this)
Basically, my winterization goes like this:
Drain fresh, gray, and black tanks,
Open low point drains, open all faucets
Remove drain plug from water heater, open pressure relief valve on water heater.
Let water drain out
Leave gray and black drains open. They should be clean.
Close all faucets.
Close water heater pressure releif, leave drain plug off.
Close water heater winterization bypass valves, (water will bypass the water heater)
Use the water pump. Pump antifreeze from either the container or fresh tank.
Open each faucet, one at a time, until pink.
Flush toilet until pink.
Open one of the water heater bypass valves until pink flows from water heater drain. re-close water heater valve.
Dump 1 cup of antifreeze into each drain; sinks, shower, wash machine (if you have one) , and antifreeze into toilet bowel.
Thats it, you should be good.
I wrote a HOW-TO for my Mirada, I doubt it will apply to you, but you might be able to get some ideas from it.
WINTERIZING / DEWINTERIZING | 2001 Coachmen Mirada 300QB