@steve-burk I like Steve's suggestion for your own problem as it will absolutely work, but in the hope of making things needlessly complex, this is what I'd do:

Create a shell script that is comprised of the commands you need to provision the route. In your installation script (you have one, don't you? ;^), check rc.local for a reference to the script. Insert a call to rc.local if it's not in there. Also in your install script, copy the route provisioning script to somewhere sensible, such as /usr/bin/. This directory is in the path and need not be "spelled out" in rc.local.

Perhaps you could write a script that takes routes as a command line parameter. As such you could easily call the command multiple times from rc.local to configure multiple routes or perhaps better yet, pass along not a route but a config file path that contains the routes you desire. If the latter, you just mod the route config file and reboot - voila!

If you're dabbling, this suggestion is overkill. If you're trending toward production, this is a bit more important and ought to be considered. Your mileage may vary.