AVIS and Hertz are expensive, however . . . there is much cheaper car hire available in Europe. And if you're heading "off the beaten track" then you don't want a large car . . some places weren't built with cars in mind.
Normandy/Britainy are good for meeting "real people" - but some of them donn't speak English! In general I'd say the French aren't the friendliest people on this planet, however (a few whis some of our French friends endorse . .) - although clearly there are "noble exceptions".
However if you are on a limited budget Spain is almost certainly your best bet . . (but then again it's our favourite country in Europe for "tourism".)
As has been noted, kids are generally appreciated far more in Southern Europe (Spain, most of France, Italy) than in the UK and US.
As for the danger of robbery - well, I'd say it was less of a risk than in the US, although "reasonable precautions" are always wise - and, of course, if you do have such problems they cause much more difficulty "overseas". (We never travel abroad without money belts!).
I'd recommend the Rough Guides (www.roughguides.com) - excellent guides (including "context" information), very cost-conscious, realistic on matters of personal safety etc., wide range of "cultural" info. as well as the "places of interest").
G.