Hello,
Starting to plan the following holiday and it will be good to get your thoughts and experiences please:

-Four weeks family summer holiday with the car From London to Spain, Italy, Switzerland, Germany, London
-Booking accomodation a day or two before arrival at the next destination by airbnb or looking for accomodation on google map or may be a day or two in tent in a nice campsite if it is not too hot...
-Car is end of 2015 model, under 9,000 miles at present and has a sat nav. So will be using the built in sat nav as well as the google map on mobile phone to find routes...
I will have the car serviced before then.
Not sure if Tyres need to be re-placed, although they look still new.

1-
catching the ferry from Portsmouth to Bilbao in spain (Around 24hrs). Already booked
2-
May be nearly two weeks in spain. Will try to avoid south west as I hear it is hot in end of July.
Any suggestions on which places to visit and drive through?
So perhaps drive from north towards centre and then towards east a few days at a time?...
3-
-drive towards Italy, via south of france. May be stay in southern france for a couple of days if we find a good place to relax (Although we have been there a few years back)
Any suggestions where to visit in Italy as the next destination will be switzerland or Austria
4-
drive towards Germany and visit for a few days
5-
No need to stay in France or Belgium as it was visited previously.
6-
Drive back to London from Germany may be a day stop on way.

Any suggestions on the route to take for this trip? especially in Spain?
Places to see?
Family is keen on water parks so I hope to plan visiting as many as good water parks as possible on route...suggestions ?
Websites to book accomodations, campsites ?
suggestions on items to have with us?
Any suggestions on t-mobile internet reception on this route?

I am getting prepared slowly but it will be good to read your thoughts, suggestions, experiences, etc. for this drive holiday.

Many thanks