How to connect polysurfaces and surfaces?

How to connect polysurfaces and surfaces (see yellow roads)?

If surfaces/polysurfaces have adjacent edges use Join.

If surfaces/polysurfaces have adjacent or almost adjacent edges and at least one of the edges is untrimmed MatchSrf can be used to pull the edges together before using Join.

If there is a gap between surface/polysurfaces BlendSrf can be use to create a filler surface for the gap before using Join.

If surfaces overlap signnificantly as appears to be the situation in the illustration, one or both surfaces should be trimmed to eliminate the overlap. Then proceed with Join, etc.