Timothy
Flying airways is not always the best option and probably better suited to long trips.
Even moving the Citation I make cost decisions do I fly the pocket rocket VFR below CAS and make the trip from A to B in 25 minutes or file IFR and take 45-50 minutes.
Flying low level IFR in the south of the UK in something like a Seneca is a pain in the kneck. Very often you are routed by ATC in totally the wrong direction and away from everywhere ATC dont want you. Your trip and costs go up dramatically. You end up thinking whether its worth it?
The same will go in many areas of Europe. Trundle down the west coast of france and you may be ok.
Then what aircraft? Is it worth struggling a typical non turbo piston into the levels to get in airways? taking all year to get there?
Go further north into Scotland and how often will you get conditions which allow you to become VMC for a VFR flight at your descent waypoint.
I actually wonder how useful in reality this EIR is going to be?
Pace