My girls and I tried to read Swallows and Amazons as suggested for weeks 16-18, but we just couldn't get into it. It has a lot of details about sailing and we just could not get past that to get to the meat of the story and really enjoy it. So, I dug around to find something else and came up with one that I think is a winner:

Theater Shoes by Noel Streatfeild

This book was written in 1945 and is set in London during WWII. There are definite war themes included. However, it is a mostly light-hearted novel with mentions of what it was like to live during the war (ie: using "coupons" to purchase necessities, the lack of goods to buy, etc). Overall, I think this is a terrific book. It could be enjoyed for just the literature aspect, but the historical details that are part of the fabric of the story make it great to read while studying WWII. I found this to be especially true since one of my girls wants to avoid anything that involves war (and the study thereof).

Just thought I'd pass that along in case someone else had the same struggles that we were having.