I have a van as well. I have owned no other type of vehicle since 1988, when I realised that being able to carry more or bigger airplanes was far more important than going fast, or looking cool! I figure that the center section and stab should be about 29" span, which isn't too bad for transport. Still, you're right about it not being an everyday flyer!
I'm currently building a 1/4 scale Lockheed Vega, and just the stab spans 42" I never thought I'd end up building such large models that I'd have to make the stab in two pieces!
You're right about not needing to glass the wing if the ply sheeting is used. I think I'd consider dope and light silkspan.
I see what you mean about about having to use heavier spars if you were to use balsa sheeting, and not saving much weight. That's the benefit of having the plans in front of you!
I have the Harry Robinson scale drawings from MAP in England, and they are very detaied, and I highly recommend them. The drawing shows an RAF 34 airfoil set at 0 deg, 54', which I have never been able to figure out!
I hope to hear from the plans service early next week...or at all since I had no reply on the first try!

Cheers, Nigel