I have found that when I travel some cities effuse warmth and hospitality while others are very difficult for a stranger to navigate. In this context, “effuse” most closely means [L.11-12.4.a]
Effuse in this context means to 'emit' or 'radiate'. The writer says that in some cities it is easier for strangers to find their way and they feel more welcome. Whereas in other cities, the locals are hostile and aren't very accepting of visitors.
