I don't think you should base it on miles. I have a coworker that has a pristeen OLD sportster that he fires up and maintains every weekend with VERY low milage. It's just like 06Vic said, how are they stored?
I put 10K on my TC in less then 7 months after I bought it so I think if you go by milage you may be deciving yourself. My 04 was garage kept, dealer maintained ridin in the summer and as a comuter with about 22K on it when I bought it. As great as shape as it was, still put almost 800 into it getting it up to speed for everyday riding.
Look for signs of dry rot, check service records, and talk to the owner to get a feel for his riding it. A new batt, tires and tune up may yeild an awsome ride! If your handy with your wrench, this forum could easily get you up and running I think if you did run into any problems. Of course, price is everything too! Me and the seller split the 800 on my bike as part of the sale.
Good luck and keep us posted!
2011 White Vision - Nuvi 550, Lowers, Lloydz 2nd filter, Vic perf filter, CB/Icom, 96 Brake LED's, Clear Signal lens/Switchbacks, VIC Hwy Pegs, Stebel Horn, 7Jurock 15" Shield, PCV, Lloyd ATS and Variable intake, Ness honkers
2004 V92 TC - S1 flash, level 1 slip-on, Ness big sucker K&N, ISO Grips, 4x1.5 Highway Hawg Risers, extra chrome (never too much), JM 2k CB 4' antena, Mustang seat, HD Front TS & Lowers, OD Pulley
Retired Navy SCPO