There is nothing that would be classified as "REQUIRED" for the riding you are planning to do.
Crash bars are worth the money [because they make it less likely that you will drop the bike..... something to do with Murphy's Law, don't have them and you will drop the bike, have them and you won't drop it
A B&B bash plate out of Australia is about the best/toughest one you will get.
As for mileage, the Wee-Stroms [and the Vees for that matter] are renowned for big trouble free miles/km's.
I was trying to find a recent post from a member here who just posted an update on his bike and what little has been done to it [he's on the second time around on the speedo from memory].
There are even some out there with 200,000 to 300,000km+ trouble free.
Mine is an 09 Wee with almost 60,000km on it now and has been totally trouble free and apart from tyres and routine oil changes it had rear pads at around 48,000km- front pads, counter sprocket and chain were done between 53,000 and 55,000km.
I do commuting, touring and dirt with mine [probably 80% tar 20% dirt-some of it mild single track as well].
Did you keep the KLR?
I have an old '87 KLR650 that I use for some trail rides as well.
AS kiwi-outdoors said, farkling/mods is a disease- but it is fun