Looking at a '83 Blazer that needs towed...
 

Does this sound legit? Would leaking valve covers cause low oil pressure and a bad idle?

It needs to be towed because it has been sitting and while it was sitting, the valve cover gasket leaked enough oil around the engine block that when the engine heats up, the oil starts to burn and smoke. It also has very low oil pressure due to the leak and so it’s hard to keep it idling...
It really is just a matter of cleaning it up and replacing the gaskets which is a matter of unbolting the valve covers and taking out the old gasket and replacing it with the new gaskets...very easy job (or relatively cheap if you pay someone to do it)....I just don’t have the time right now...
There is some surface rust in the wheel wells and a little rust by the back tailgate....
The AC needs to be recharged in order to function...
All the windows work...they are all manual.
The speedometer works but is off by 15 mph and needs to adjusted (I think it has a slight lift and whoever did it didn’t adjust the speedometer...)
Other than that it worked well for me while I drove it....
If you bought it and we’re willing to put a few hundred bucks (or some elbow grease) into fixing it up, it would be great...
I am negotiable on the price...
Hope this answers your questions! Let me know if I can answer anything else for you...

I see virtually no rust in the pics provided but there are a few areas I can't really see very well. I'm comfortable doing the valve covers myself, sounds easy enough anyway, but without being able to test drive it I am real leery about forking over almost $2k based on the sellers word.

A valve cover leak will not cause low oil pressure. Maybe if it was two or three quarts low, but assuming it's less than a quart low, there will be no drop in oil pressure. I've drove plenty of cars with bad oil leaks, and it's never dropped the oil pressure. Oil pressure also won't cause it to idle bad, either.

Low oil pressure usually = bad sending unit and or gauge [ sending unit could also be the leak ], worn oil pump, worn cam bearings, worn main and or rod bearings.ECT

Also a lift shouldn't throw speedometer off. over or under sized tires from the stock size will.

"AC needs to be recharged" usually means "I took it to a shop to have it fixed and they told me the compressor exploded, scattering shrapnel through the whole system, so everything needs to be replaced.

Sounds like either the seller knows nothing about cars, or is hoping you don't.

I leaning towards the latter...

Thank you @Tom A, @cleburne red, @odat for the replies.

This is where I was leaning also but I guess I was hoping he was both knowledgeable and truthful. Obviously since I had to post the question I am in-fact lacking in knowledge, but have just enough to know it sounded a bit off and to ask the experts. The body, from the few posted pics, is really clean so I'm a bit bummed. The search continues.

Personally, I would look for a newer one (1987+) with TBI instead of a carburetor. They're easier to work on and run better, IMO. You'll also get the new style rear main seal that leaks less.

Or get it for a reasonable price which will allow to fix all the problems.

If it was a truck I wanted to have I'd make an offer that suits me, not him.