方面 and 方向: toward an area and a direction of movement
Compare a bus heading toward a hot-spring area with wind direction, separating a regional heading from confirmed arrival or stops.
Toward a region or destination area
方面, read ほうめん, indicates the general area or destination side. このバスは温泉方面へ行きます。 says that this bus heads toward the hot-spring area.
大阪方面の電車はこのホームから出ます。 says that trains heading toward Osaka depart from this platform. A regional heading and each train’s terminal station require separate attention.
The way something moves or points
方向, read ほうこう, means a direction of movement or orientation. 風の方向が変わりました。 says that the wind’s direction changed, without naming a city or region.
矢印の方向に進んでください。 asks someone to proceed in the direction of the arrow. The arrow supplies the reference for movement.
A regional heading and detailed route information
海岸方面へ行く describes going toward the coastal area, while 海岸の方向を指す describes pointing toward the coast. They can indicate the same general side, but the actions differ.
温泉方面へ行きます alone does not confirm a stop at the hot-spring entrance. Identifying a direction and identifying the desired stop are separate tasks.
Does a bus that 温泉方面へ行く necessarily let passengers off at the hot-spring entrance?
Show the answer and why
The expression alone does not establish that. It gives the general heading, so the entrance stop must be checked separately.