If it has not been done, swap out the S&S rectifier for the Harley unit.
Peace of mind.
John.
+1 on this. Cheap and apparently nasty regulators from China via eBay just work, the standard one just fails. Best change it in comfort before you have to.
Some imperial and metric Allen keys.
Same for spanners; car is mainly metric, engine mainly imperial.
A trimmed down spanner that fits on the inner tube securing nuts (17mm from memory)
Plug type puncture repair kit for the rear, you don't want to have to change it if you can avoid it outside of a comfortable and reasonably well kitted out workshop. But take a couple of spare rear spindle nut split pins with you, they can fight back when re-used though are usually ok.
Last autumn I did a 4000 mile trip round Europe and only used three Allen keys in the whole journey. One to drain the oil catch tank that I have fitted and two to screw back together a cheapo H4 headlamp LED that had vibrated apart. I had an extensive and heavy toolkit with me, virtually all of which remained untouched.
Exhaust mount bobbins; take a set of them, they have a tendency to fall apart after a while.
Duct tape and some lock wire will sort out many things when necessary.
Enjoy the trip...how many miles are you looking at?