In beer league, I think it's easiest to play a system by stressing concepts rather than strict adherence to a plan. Get your players thinking about why you'd play the system instead of what to do in each situation. Adults don't typically want to be told what to do, but they will try to try if you explain to them why they're doing it.
For example, instead of telling a wing, especially a weaker one, all of the things he would need to do in a box+1, get him to understand shooting lanes and the high danger areas of the ice. Then just tell him to not let the defender get the puck through those areas, but he doesn't have to be right up on the guy or all the way down in the circle either. He likely going to be out of position in relation to the overall system, but he may still be effective in keeping pucks from the point from getting through. If you can get everyone on the ice to do their individual job at some level, even if it's not a fully functioning system, you'll have a lot more success.