Leg press, deadlifts, RDLs, lunges, leg extensions, leg curls, hack squats, split squats. All those will hit your legs, plus there variations. Do some sprints, run hills, stairs, those will hit your legs. Im sure there are more lifts I can't think of this second as well.
While natural gas occurs in nature as a mixture of methane and other gases, propane is actually a byproduct of both petroleum refining and natural gas processing.
Propane normally changes from a liquid to a gas at -46 F (-43 C). However, propane has the nice property that when you compress it, it condenses into a liquid and will stay that way until it is uncompressed. This means that propane is much easier to store in a tank than natural gas, which does not easily compress. Because natural gas doesn't compress well into a liquid form, it is typically delivered via a dedicated pipeline to your home.