I've had quite good luck with a 50/50 mix of acetone and the cheapest ATF I can find (seems to be Ford branded..... go figure. .) PB Blaster is pretty good. There's also Aerokroil, but that can be hard to come by.
"Measure with micrometer, mark with chalk, cut with fireaxe." Ted M., USCG (ret)
"Smoked pork. It belongs in me." Giles L
Wd40 makes a pretty good penetrating/rust oil that I have used with success. The biggest problem is getting (any type of) oil into the hub in the first place. You might be able to drill a hole in the wheel hub--just thru the hub, not the axle--- and work some oil into the center section between the hub and axle. May need to drill a few holes depending on the rust buildup.