I did 6 months from LA to BA on a 2005 KLR 650.
I found that:
Larger tank - not needed
Suspension upgrade - maybe but then again why not just save the money for
and repairs if neede.
Off road footpegs - definatly needed
quality handguards (to avoid levers/fingers breaking) - needed
alu bashplate - not needed, waste of money
highway pegs (whitehorse.com) - cheap and very comfy, but not needed
quality rack from happytrails.com - good and cheap
alu boxes - not needed, keep your weight down instead
aftermarket seat - save the money and buy a sheepskin
quality handbars (renthal alu) - maybe an ok investment, but then again...
heated handgrips - needed! I froze my hands too much without...
taller windscreen - try taking the standart off instead, works very well
quality sprocket and quality chain - needed and worth the money
a set of jets to tune the carb to altitude - needed! I really missed having them
upgraded gearshift lever if you have big feet - The IMS is nice quality, but I wouldent bother if the standart fits you fine
upgraded brakes (larger disc and steelbraided lines) - I havent tried the stock, but even the fully upgraded one didnt ever lock the brakes. Depending on driving style this is needed/not needed.
scottoiler could be ok, but you want something that can use whatever oil you have at hand.
centerstand - would be nice, but too heavy and lowers groundclerance
I had alot of stuff on mine, and if you ask me how I would do it another time, this would be my ideal setup:
By the lowest mile 2005-2007 KLR 650 you can find.
Put handguards, offroads footpegs on. Use throwover softbags.
Drive off and spend the money on fun instead...