I know plenty of people who have read on Kindle. You shouldn't NEED the maps or family trees to understand stuff, especially if you've watched the first two seasons.
All of the maps are available online (http://www.westeros.org/Citadel/Gallery/Category/C34/ for example, with all but maps #5 and #6 being official) so you could just look at them some time on computer. Especially since after 2 seasons you can look at the maps now and pick out the important landmarks (Winterfell, King's Landing, the Wall, etc) so you can get a general sense of geography.
There are listings of all of the characters in the appendixes in the back, but not in "Family tree" form as much as just family listing. I've never really cared for them actually, as I prefer stuff like the wiki of ice and fire that DOES have family trees, but it also has TONS of spoilers so I wouldn't suggest that unless you've read all of the books.
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