Enumerating Trust Relationships

# Using Get-ADTrust
Import-Module activedirectory
Get-ADTrust -Filter *

# PowerView
# Checking for Existing Trusts using Get-DomainTrust
Get-DomainTrust

Get-DomainTrustMapping

# Checking Users in the Child Domain using Get-DomainUser 
Get-DomainUser -Domain SUB.DOMAIN.LOCAL | select SamAccountName

# Bloodhound can also be used