It's not that hard to enter:
a2jmidid -e a2jmidid -e
into a terminal and hit enter and connect the keyboard to Reaper when I am doing MIDI work but it is a little bit of a pain.
Is there a way to make it automatic? It is too bad that we have this minor annoyance running Jack and trying to run MIDI. I do like Jack since I can do things that would normally break my system (i.e. unplug the sound device without a crash by stopping Jack first). Sometimes this seems to crash the OS if not in Jack. I'm learning to love it in other words even with some minor bothers here and there.