The "fuel nipple" on the engine, typically between the crankshaft bearings, is a vent/drain hole. it just allows blowby gasses and oil to exit the engine. The blowby gasses and the oil that gets by the piston is where the internal lubrication comes from. You just connect that to a piece of tube if you want to route the dripping outside of a cowl and let it drip.

The muffler pressure line and carb fuel supply line are basicly the same as on a 2-stroke, unless it is a pump equipped engine. If it has a pump... then the manual wll tell you how to deal with it.