If the 700 hours is true, 11,000 sounds fair, especially if the snowblower and chains are in good shape.
The 345DT was a very good tractor - I ran one for about 1100 hours with very few problems. I sold it for 12k with just the loader.
These have a 4-cyl engine that runs about a month on a tank of fuel. Mine developed an oil leak at the top of the front engine cover - but it was an easy fix once I figured it out.
I'm assuming it has the kubota 1720 loader - nice unit with plenty of reach and power. (Bigger than today's loaders for 34 hp tractors)
Check the 2-stage clutch - make sure the pedal can go far enough to disengage the pto. If the drivewheels clutch is worn the pto becomes full-time until the worn clutch is replaced.
Hope this is useful. Let me know if you need any other specs for it - I kept copies. Also go to the archives of this forum where Randy Diakur and others discussed 345's