I'm going to break with the others here and suggest not pedaling while standing. I think that's a way for a new cyclist who's not yet in shape and carries extra weight to get injured. Stand and coast for butt relief, sure. I've been through this. My mantra for 1st six months was "no injuries...".
It takes months to strengthen all the connective stuff around the joints. Muscle strengthens so much faster. Extra weight makes it really easy to overload knees, etc.
btw: good goal, good suggestions on how to get there.