What's the concern about 1970's fabric? If the plane has been well cared for, the fabric is of little concern. I have a '72 Super Viking with original paint and fabric. Overall, the fabric is in great shape. Sure, it's got a spot or two that have been touched-up over the years, but nothing of any real concern (many metal airplanes have similar blemishes). There is basically no other certified airplane on the market that can match the value of the Super Viking. They're far from perfect, but we paid $35k for ours, with a 400hr engine, a new prop, and 2300tt, a 430 and a KX165, and it'll make 155-160kts on 13-15gph (LOP). Useful load of 1125lbs. It's a little tight inside, sure, but the price simply can't be beat. You need to be able to hangar it, though.
While $35k was a steal for ours, you can buy a good specimen for well under $50k all day long, usually much closer to $40k.