For mine, i wanted to allow pings from anyone, admin access from my remote subnets, and then deny the rest. Here is the config, modify the interface names as needed, I used an Address Group for the allow rule.
config firewall local-in-policy
edit 1
set intf "wan1"
set srcaddr "all"
set dstaddr "all"
set action accept
set service "PING"
set schedule "always"
next
edit 2
set intf "wan1"
set srcaddr "Admin Subnets"
set dstaddr "all"
set action accept
set service "ALL"
set schedule "always"
next
edit 3
set intf "wan1"
set srcaddr "all"
set dstaddr "all"
set service "ALL"
set schedule "always"
next
end
After implementing this you can remove your Trusted Hosts configuration as it has become pointless. I feel this solution is much more flexible, the only downside is that you can't see or administer it through the web interface (yes, even if you enable the Local-In Policy feature, it's still not there).