Welcome to the Forum !!
First - great signature line "Southern Cross" CSN reunion LP titled 'Daylight Again" - 1982 (I think) as pretty a song as there ever was since "Helplessly Hoping" CSN 1969.
Second, the seller of this boat, PineTrailCamp has EXCELLENT ratings by other buyers. Not that it couldn't happen, but I have a feeling that a non-profit is not looking to mess anyone up. Also possible that you could buy the boat, declare "value in kind" of, say, $600, and write off the rest of the purchase price as a Charitable Donation on your taxes.
The boat was probably a donation to the camp, so whatever they get is for their program.
Third, I think the boat is a pretty good deal and definitely worth $1000. The trailer alone is probably worth $500. Sport or SE doesn't matter. I like the full-boom rig because it allows better tuning and sail shape.
Trailer hitch - A little scrub with WD-40 and steel wool, followed by Rust-Oleum rusty metal primer and your favorite color paint. I doubt there is anything wrong structurally. It looks better than mine.
Repairs to starboard hull - In my experience as a Camp Director, things that get repaired are usually done by a "resident expert" volunteer who knows what he's doing. Usually. I am REALLY interested in how the repairs were done however. E-mail pinetrailcamp and ask them how they were done. I THINK that someone actually cut the deck out around the wing-sockets to repair and then glassed them back in. It doesn't look like a "deck-plate" as such to me.
The sail looks dirty. That happens when people don't store them properly. Not too hard to clean. Again, ask the seller if it is delaminated.
The tramp looks newer or is an upgrade -I think standard issue up until about 1990 was a solid vinyl tramp with a diagonal lashing. Wings too.
I would definitely replace the standing rigging if it is original and perhaps the sheets and halyard depending on wear.
Last is a question for Dan - 190 lbs ea? We got a 17 up with 330 lbs just two weeks ago and I can get it up with a solo-righting kit myself at 155 lbs- no Hobie bob. What is the recommended weight ? I have no idea, I just know what works