I'm 6'7" and have a 98 RD07a. It feels like the bike was custom made for me, although I do suggest you fit a taller screen. I have a lower Corbin seat which I got with the bike, and even on that I'm quite comfortable.
Do a search on this site for common problems. This might be a start though it's not the tread I had in mind.
My advise is that if you only check one thing before buying that it should be to listen for any strange noises coming from the output shaft. These are easily damaged if you run the chain too tight and is hugely expensive to fix. Other common problems on the RD07 is the fuel pump and regulator/rectifier and they do tend to dissolve a bit when left covered in road salt.
'98 Black AT, Motad Crash Bars, Baglux Tank Cover, MRA Variable Screen, Centre Stand, GIVI Topbox, Renthal bars, Touratech Handlebar risers, Heated grips, 12V socket, IMS Pegs
Dropped = 3
'02 KLR650 AT Handlebars??! & lots of plans.
Dropped = 2