First thing to do is forget about Gatwick - unless you are taking out a mortgage for the landing/handling/parking. Use a smaller airport, especially if you are parking up for more than a tech stop.
IFR charts/plates are expensive over here. You can look up plates on the individual AIPs for each country - see the FAA international flight information manual for useful details about each country. Charts will have to be bought and Jepp are as good as anything.
Make sure you have a laptop - you will need to gather your own weather info and file flight plans (unless you are paying a handling agent). Getting to grips with the Eurocontrol routing computer is a dark art; don't despair if it takes multiple tries.
There is no such thing as "cheap avgas" in europe......