Battery and Drive Unit warranty on the 60 is mileage limited (150k), while the 85 has unlimited mileage. So do check how much is left.
There is at least one account I recall of a failed 60 battery outside warranty, and that was a 13k$ replacement cost if memory serves.
For the 60, do also check if it can use the Supercharger network (aka SuC). It was an option on the 60 (included in the 85). Your might not think you need the SuC, but you would not be the first Tesla owner who started road tripping just because it's such a great car to roadtrip (*).
For both, do check if they have the navigation enabled: yes, all Tesla have the Google map, but that does not mean it can do turn by turn navigation. In the early days, the navigation part was an option (eg Teck Package).
As mentioned above, MCU is an expensive repair (2000$) that I experienced in my 5th year, with the car around 190k km/120k miles.
Door handle are expensive to replace (500$ ?). A little less to fix. (200$)
I have some noise coming from the front suspension, guess sway bar links or other components will need replacement too. If you are a DIY guy, you can find help around the forum on how to do some repair yourself.
Other than that, even the most early years cars are amazingly great to drive. Even without AP.
So do not underestimate the cost of ownership. If you're fine with it, hope you join the Tesla family soon !
(*) Side note, before "hell brakes lose": 60 and 85 (and early 90) batteries have had their SuC speed reduced. Some owners concluded they cannot roadtrip anymore due to this. I personnally still roadtrip twice a year (summer and winter). We had planned a roadtrip to Italy this year, but cancelled it over Covid. Looking forward to our winter trip, hoping this one will still be on.