you could get buy with a old cast iron pan or bean-pot on a propane burner, whitegas stove or even an open fire if you really want to be 'Old-school'.

I've never worried too much about hardness, the powder coat acts as a kind of "jacket" that has it's own hardness. I generally do some range scrap "alloy" mixed with some pewter for mold fillout. This makes pretty accurate bullets in my handguns that don't lead.

The Cast Bullet Handbook by Lyman is well worth getting, it is full of data for all kinds of cartridges and references molds from other companies besides Lyman which is nice.

I've shot thousands of my own cast .38 wadcutters and they have beat or at least been equal to off the shelf cast bullets from Hornady.

The CE harris "universal load" of Alliant/Hercules 2400 under a cast bullet in basically all full-power rifle cartridges is accurate in everything I've tried it in as well. Unless you are loading magnum pistol, and some rifle, powder coating eliminates the need for a gas check at lower velocities.