Dutch Douglas Boston DB-7B

I think the top surface colors were a very close match to what the RAF was using during the period. Color photos of various aircraft would seem to indicate this. The sky color applied in the USA appears to be a bit different however. Robert Archer's book on USAAF camoflage in WWII suggests 12% light blue No. 307 and 88% white will yield the sky color applied to USAAF aircraft during 1943 for aircraft in the Northwest African Theater. I'm not sure if this was the same color used for aircraft going to the U.K. The F.S. # for sky in the ANA bulletin dated September 28, 1943 is 34424. (ANA code 610).
I think a superb resource for the A-20/Boston is the AJ Press softcover book number 41. Full of great photos and scale drawings, this is a must have for building an A-20/Boston!! The text is Polish with English captions.
As for the interior...it would appear to have been the common Zinc Chromate green with black instrument panel and side panel boxes.
Hope my 2 cents worth helps!

Joe

Arie I think that Air international is a good starting point for drawings.

Have to agree with ninedriver,the A&J book is one of the best on the A-20,suggest you get the late Paul Matts dwngs on the A-20 their excellant,also a copy of Historic Aviation Album with the article on A-20s its still available but you have to do some digging on who has it .Its worth it.