Main areas were where the quarter panel meets the sill infront of the rear wheels, over the arches filler cap area. Anywhere dirt and or water can pool really.
Usually find seaside cars are the ones to avoid, salt kills everything
As for insurance, you will find the purchase price has little to no influence of annual cost, a 2k Z will cost the same as a 9k Z its the up keep that will differ massively.
Other things to look for are Oil level, regular services etc etc but I don't think they will be an issue on that one, seems to have had a loving home.
Happy hunting