Its an easy trip. Ostende is recommended. Schipol is now too expensive for this kind of trip sadly but I did that as a PPL training cross country when it was about 50 guilders landing fee. calais is also easy (but mind the prohibited zone near the airport) .
the essentials checklist =
flight plan both ways
GAR for coming back , with sufficent notice ( can file before you leave in fact) plus customs notification on return ( part of GAR process) .don't have to use on line form, can just do by email.
interception procedures copy
passport
evidence of VAT paid/free circulation of the aircraft
aircraft docs
pliot licence/medical/passport
PLB or ELT depending on state of registration
notification to the customs at airport of entry withing their notice requirements
flotation devices
fuel drawback/date of last foreign trip the a/c made - not required but obviously worth having
mode s transponder where required by countries/airspace visited
weather both ways/outlook for later/alternates that don't need prior notification....
Hope that helps. Its no harder than any other flight except the GAR form / customs notifications really.