My 3yr old can go under the water confidently, but we all know running water is a lot different to pool water
The bath is an awesome idea.
@hoyle3 - what did you want to know exactly? just places to go/avoid, things to do, and (as you said) other people's experiences - that is whether or not the kids actually enjoyed themselves etc?
If you want an extreme view of travelling with kids... get hold of some of Dervla Murphy's older books. She took her little daughter to the most incredible places... including the Karakoram in winter... just her, the girl (aged 6) and a pony! Sure, the media howled their protests, but now the girl is grown-up with kids of her own and she's often taken them travelling like that!
Mind you, Dervla Murphy made a comment in one of her more recent books that taking her grand-children to a London park for an afternoon required more planning and equipment than she would have expected for a Himalayan expedition!
At that age the thing I most remember is carrying them when they got tired. We have three children of similar ages, so they used to walk and get carried in turn.
When they get a bit older, audiobooks in the car are great. I remember listening to the whole of the Alex Rider series while driving round Ireland.
If you take them walking the odd dose of carbohydrates in the form of chocolate drops can often revive tired little legs to a magical extent.
First of all keep your kids from water as long as they can not swim.... Best way is to mind your children constantly, do not shun water but also do not camp just near it. So we never camped that close to the edge of water as long as our kids hadn't a 'conscience'.
You know telling your kid don't do that and five seconds later they still do it? Well in that phase better stay away from the edge of water when camping...
About swimming lessons, that really doesn't work that well under the age of 5. Better is to search for water training for todlers. In those training they 'learn' what water is and to trust their capabilities to the level of what they really can do and learning what they really cannot do (swimming....)
And always take them with you in the water, take some floating safety stuff which you have to inflate with you on a hike. It's compact and reasonably light. It's fun!