I put about 20-30 kg of stuff in my bike panniers. Or you could perhaps get an cargo bike. I know a grandmother here in town who got one to transport her grandkids. 30 kg for 10 km isn't much; you could get an electric one if the distance or hills are an issue. Probably beats a owning a car in most ways if you don't driver longer than that daily. I live in Uppsala, 60 degrees north in Sweden, Europe (and manage a pool with 25 vehicles; both bikes and bike trailers). But people seems to start using cargo bikes in the US too.
(there are legitimate reasons sometime for using a heavier vehicle like a car, but people claiming "I have to save a few minutes more of commuting" in many cases actually don't save that much time - if you take in account the cost of driving. Also, putting breathable air at risk for some convenience if you actually can go bike bike or transit seems a bit selfish