Best penetrating oil that I have found is "Deep Creep" by Seafoam. Don't forget to spray around the studs, because that is where it is stuck. I would put the lug nuts back on, and leave them a bit loose. Then take it out on the road, and at 5 or 10 MPH, slam on the brakes. Many times this will loosen the wheel. I use to do sharp figure 8's in the shopping center parking lot on a Sunday when everything was closed, but today, all the stores are open on Sunday. If you know someone with a porta power, you can put one end on the bottom on one rim, and push on the other rim. It might get one loose or two, depending on how stuck they are. I am not a friend of beating on the rims with a hammer, because you run the risk of bending them. A friend has a very large, (3' long) dead blow hammer that he wacks the rims with, and it works great to break them loose. I used a 2" x 12" x 24" long and laid it next to the tire and rim, and would smam it with my sledge hammer, sometimes it would work, and other times, it was a waste of energy.
Edit............. Use your "Hotsy hot water pressure washer"!!!!!!!!!!!!!!!!!!!!!!!