There's certainly plenty to see in Tunisia presty and I'm sure you'll have a lovely time. Just remember that transport is cheap and many trips can be done without the services of your rep. Just have a look around this forum and it should give you plenty of ideas.
Haddy - you have my deepest sympathy.
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I, of course, am a perfect mother-in-law, though I am well aware that not all are as superb as me. At least you will have the first week to yourselves though - perhaps you could change hotels for the second week so she won't manage to find you.