It'll be good to see what you end up with. I nearly bought one 3 weeks ago (new) which was going to cost me around the 15 k mark. Then you need to start spending?? Luckily a pristine 640 adventure came up with around 4 k on the clock and I saved around 5 k on the 690 with no need to modify it too much. So I took the easy option. Albeit with a bit more vibration than the 690 donk. Good luck with your project.
KTM250 EXC-F FOR THE TIGHT STUFF
KTM640 FOR THE DISTANCE
SUZUKI GSXR750 FOR THE BLACK WINDY STUFF