Two G5's stacked vertically with an Aera 660, a Gtr200, and autopilot 507 with servos may be as cheap and (but very functional) simple vfr machine as you can get.
From there, if you want to add a few k extra swap out the Aera for the 10" G3X panel.
If you want it to be IFR, add a GTN 650 or 625 and GAD 29......and the the audio GMA 245.
Search RV8 panels and you'll get some nice ones
St. Johns, AZ (SJN)
Worlds longest RV build...but getting there