On Windows, how to determine route for IP destination?

In Powershell:

Find-NetRoute -RemoteIPAddress "10.0.0.34" | Select-Object ifIndex,DestinationPrefix,NextHop,RouteMetric -Last 1

ifIndex DestinationPrefix NextHop     RouteMetric
------- ----------------- -------     -----------
     49 10.0.0.0/24       10.64.130.4           0

Yep. Open a command line and type tracert 1.2.3.4

The pathping command is similar to tracert but includes the outgoing interface.

Using cygwin, this command gives the outgoing IP/interface for a particular destination (specified by $HOST):

pathping -n -w 1 -h 1 -q 1 $HOST | head -n 4 | tail -n 1 | awk '{print $2}'