Welcome to the forum!
I can't give specific advice on the Arctic Cat.
What I can say is to give it a THOROUGH inspection, especially being a farm unit which probably got more work than a unit that's for trail running. 800km is easy for trail riders. 800km on a farm could have been easy things like doing fence runs or it could have been harder work.
Things to look for:
Check all axle boots for rips or tears. (Can't speak for this Cat but my friend had a Cat ATV and it was quite a chore to replace them). Also check all joints on the axle and suspension. Tug on the tires to make sure bearings and joints aren't loose.
Look underneath for any dents or bends from driving over things. Fence posts, barb wire... all have a way of finding their way under these machines on a farm.
I see the plastic below the winch fairlead is cracked. Is there any damage to the metal behind it? Where's the winch cable? Odd that it's not there. Does the winch work? Why is the fairlead plate beat up?
Are there any maintenance records? Looking for regularly scheduled service, belt replacement... Check the drive belt cover. Does it look like it's been opened (to replace the belt)? You may want to open the cover yourself to check the condition of the drive belt.
Drive it around. Listen for any noises that shouldn't be there (bangs, squeaks, rattles...).
Basically, give it the same inspection you'd give a 10 year old car that "may" have had a hard life.
