Limited Space, Time and Resources

I have been working out for almost a year, but since winter started I have found myself very limited to the exercises I can do. I work full time, have a child and live in a very rural area. My nearest gym is a half hour drive away and walking/running outside in the dark is out of the question as it's not safe until the evenings get longer. Can anyone recommend exercises for me? I have a treadmill and run almost every day on it, have a multi-gym that I use and kettle bells and free weights. I'm limited for space so I've been going back and forth between a few exercises (squats, swings etc) that I like, but find myself getting bored easily and not feeling it anymore. I would preferably like exercises that give maximum effect in the short amount of time I have every day to exercise. Any suggestions would be appreciated!