How do I set up lighting for a scene with both interiors and exteriors?
To avoid overly bright exteriors reduce the Sky Strength in the Bake tab to 0.5-1.5.
This Strength is not sufficient to illuminate interiors, so to make them bright you need to add artificial light sources in all the rooms and/or use Ambient occlusion(configured in the Bake tab).
ℹ️ Ambient occlusion is an ambient lighting technique which does not require light sources and is not physically-accurate, but when used moderately it gives good-looking results. A distance of 1 [m] and a factor of 0.05 are good initial values to try.
To reduce the number of lightmaps and the baking time, set Custom lightmap resolution in the Objects tab for large objects in the scene exteriors, such as the terrain, neighboring buildings, or plants. Usually, a value in the range 10-20 should be enough to sufficiently illuminate such objects.