Agree 6k is too high. 4.5k is good if there are no big gotchas lurking.
Fan failure is very common. There is a service notice on this. Fusebox contacts typically melt. I'd be surprised if your current 1986 has not had this problem as well. Most were fixed long ago under warranty. Could be more serious, but it's not going to be a dealbreaker.
Antenna masts kits are available for about $40. Did mine a couple of months ago, though sometimes the mechanism is not repairable. If mine died in this way, I would just get a cheap aftermarket replacement. So you lose some height settings- big deal.
Door check straps are a common and cheap replacement item.
I'd ignore these relatively minor problems and focus on the big-money items. Engine condition, oil leaks, suspension/steering problems (these add up to real money quickly), air conditioning.
Even at $4.5K, you get a bad deal if you need to drop $3k+ in repairs.