I have a 78 Tartan 30 and its a good boat. The safety of the A-4 should not give you pause; just be careful about gas below. Make sure the tank does not leak, mine had been repaired when I bought it and is now fine. I understand that that is a problem with these. Have a mechanic go over the engine; it is old and may be tired. Get the Moyer marine manual if you buy the boat. Get a CO detector, CO is a greater risk than fire.
The PO added wheel steering... I wouldn't have, but a wheel is easier for guests. Only sailors have steered with a tiller...
SailingFool is absolutely right about the stern ladder. It is not a safety feature if you sail alone. Jacklines harness and strong leads will keep you aboard the boat, a ladder will only help if there is someone aboard to stop the boat and let it down, and only if you are awake and strong. A stern ladder is easy to install on this boat, however, so it shouldn't be a dealbreaker