Lots of threads on this topic

Some suggestions
1 - Get your quote to be all in, ie includes, tax, liabilty insurance [collision normally covered on a cc], extra drivers if needed

2 - decide if you want to get the car at the airport [or nearby] when you land or take a cab and get the car the next day delivered to where you are staying [the latter is our approach - if you decide to go that route, try Wilfred Brooks, a TTOL sponsor]

3 - 6 people and 1 car is a lot, you will need a large car, which is not so friendly on the roads, consider 2 smaller cars so you can split up some days if desired

4 - we print the Fr and Dutch bridge and causeway opening times and put the list in the glove box for reference - very handy

Have fun
J&B