Step ups = Good.
I've been lifting for my legs (leg press sled, squat, step ups) for 4 weeks now and just yesterday I clearly noticed that the step-up has improved my power output during short steep-ish hill sessions while pedaling in the saddle.
I find that I can maintain a high-ish gear while seated during short climbs and at that cadence the downstroke feels exactly like a step-up. I feel like i've gained some power in these situations by doing the step-up and that I can continue to put out despite lactic acid buildup, which happens near the end of 10-15x each leg sets of step ups.