Hello Firecat!
For buying a used bike, if your not that confidant, may be an idea to take someone with you who knows the score. Saying that everything is basically on display on the SV's, on both N and S models. With that leaks, corrosion, lumps and bumps etc etc are pretty easy to spot. Main things I'd check are if the fork legs are wet (bad), wear on chain and sprocket, wear on brake pads and disks and condition of tyres. If you can, get the dealer/owner to start it up from cold as any niggles are easier to listen for. Pretty straight forward.
I'm on my second 650s at the moment. Great bikes!
Best of luck!
