Wow, really sorry for the response lag. I somehow don't get notifications from this forum.
The document "Swarmifying Solo" is a good start. But it isn't enough. I wanted to use a single wifi base station with all devices as clients, instead of multiple interfering wifi base stations.
It's trivial to get the Artoo and Solo connected to the LAN (basic linux networking, wpa_supplicant stuff) but the hard part is routing mavlink and rc packets correctly.
Here's a list of the network services / ports on the Solo and Artoo.
If you don't want the remote control in the loop, it's easy - just blow away the telem_forwarder process and replace it with your own, or use iptables rules and static routes to forward the packets from telem_forwarder to whatever destination you'd like.
If you do want the artoo (remote control) in the loop, it's more complicated. First you need to make sure RC joystick messages make it from the Artoo to the pixrc process on UDP port 5005 of the Solo, and that Mavlink messages make it from the Solo (telem_forwarder process) to the artoo (telem_ctrl process on port 14550). Also the telem_forwarder on the solo subscribes to the RC button interface on the artoo TCP port 5016. If you get these three things set up then the Solo and controller will work normally as clients on an access point. To connect a GCS to it you'll need to either connect to telem_forwarder's secret API port (14560) or replace telem_forwarder with your own code that connects to the Pixhawk via serial and bidirectionally forwards traffic over UDP (or whatever protocol or medium you desire)