I'll ditto the PB Blaster. IMO it works far better than Liquid Wrench. It's also readily available around here, including places like Wal-Mart & Target.
Kroil I consider the equal of PB Blaster, but I've never seen it locally. Have to mail-order from places like Eastwood or Kano Labs (the maker)
https://www.kanolabs.com/
I've been told that Sili-Kroil is even better than Kroil or PBB; but haven't tried it myself (yet).
Patience seems to count for a lot with the PBB or Kroil. I squirt a little onto any joint I think will give me trouble, then do something else for a bit (like the easy bolts) and come back. If it still won't come off, leave it overnight and try again. The stuff seems to continue to work for a long time; I've had things finally come apart after a week of trying every day (and adding more PBB).
That said, any penetrating oil is only useful for situations where the problem is steel corrosion, IMO. If the joint is just extremely tight (eg rear hubs on the axle of a TR3); or it's aluminum that is corroded (Stag head studs); then penetrating oil is a waste of time.
BTW, the folks who make WD-40 have said that the WD stands for Water Displacement and the 40 means it was the fortieth formula they tried. Works well enough for short-term water displacement, IMO, but not penetrating oil. I mostly use it on steel parts that I've just degreased in water-based solvent (aka soap and water).