Here's a summary
The following is a list for a long trip abroad consisting of multiple legs.
General:
Charts, printed & electronic.
If using old ONC charts (Greece etc) mark up CAS/DAs on it from a current flight planning program or from an IFR chart
VFR airport charts (e.g. Jepp Bottlang, Pooleys if in the UK)
IFR charts for destination & alternates (on a VFR flight this would be in case of a weather emergency). Verify that Jeppview contains them too.
Plan routes outside CAS (often this is an impractical route) and plan a preferred direct route. Plan it on VORs, NDBs, airway intersections if aforementioned not available. On VFR flights, always route via an airway intersection located on an international boundary; the EET to that waypoint is required for the flight plan. Plan to fly as high as possible if VFR, VMC on top perhaps (but don't fall into the trap of arriving at a destination when still above an overcast layer! - plan for a DIY descent below the cloud far out over the sea if needed in such a case). Plan for FL080-FL160 if IFR, or if required by terrain.
All planned routes are drawn on the charts, also loaded into a laptop running Navbox and Flitemap, and also loaded into a portable GPS. Make sure you have both wifi and GPRS internet access, and SIM cards are topped-up.
Telephone each destination to check for unusual requirements and then fax them with details to obtain permission where required. For dodgy airspace, or where CAS transits will be seriously desirable, telephone the relevant ATC units and ask for their views and any suggested routes. If there are mandatory VFR routes shown on the charts, check with ATC that they actually care (usually they don't care and will clear you direct at FL080 or whatever on the day) but ensure you have a means of flying the routes (with a GPS, obviously) if pushed. Most phone numbers in Bottlang touring guides (and AIPs) are duff, this is the time to dig them all out! Top tip: phone the ATC (tower) number of a nearby big airport; they will have ALL the right numbers. Take the list of numbers with you.
Top up oxygen bottle. You won't be able to get it topped up until back in the UK. Check cannulas. Check dates on batteries in emergency gear, flatten and recharge all rechargeable ones. Replace batteries in torches. Cameras etc.
Day before the flight:
Pack stuff for the boot, into three categories: a) stuff to remain in the boot; b) stuff to take out at each stop; c) stuff which will partly remain according to point on route (e.g. heavy touring guides). Pack clothes, food, etc. Passports, licenses.
Get notams, for all routes for the planned time windows, from ais.org.uk. Redo the notams before each flight, and (not having a printer) save them on the laptop. Put together a transparent folder for each flight, containing the plog, chart sections, approach plates / SIDs / STARs, notam printouts, PPR confirmations, etc.
Charts sequentially numbered and placed sequentially in a cardboard box.
Get weather, for next flight only if staying at 1st destination for a few days or more. Long TAFs if available, MSLP, GFS (various parameters incl. skew-t forecasts)
File flight plan (fax to departure, or
www.homebriefing.com)
Morning of flight:
Telephone departure to make sure they have the flight plan.
Get TAFs and METARs along the route, SigWX, MSLP, etc, and most recent ascent (skew-t) to check likely icing levels, cloudbase and tops.
Fax destination if they need notification on same day.
Passenger beiefing.
Load 1st route into panel mount GPS.
Go and enjoy the view from high up. There is nothing else to do but twiddle the heading bug and change tanks every so often.
Upon return:
Retain notam printouts and airport receipts for 1 year after flight. Airports often bill for landing/parking again (months later) and in the absence of receipts one has to pay it again else they stir up trouble through the CAA or the N-reg trust company.