-How can I determine if a user on this forum is worth transacting with? Is there a feedback/rating system?
Every forum member has got his trust rating. Look on the left, there is "Trust" rating visible below member's nickname. Also you can visit his profile to check it.
For example here is yours:
https://bitcointalk.org/index.php?action=trust;u=511554-I heard that if you sell via PayPal and ship some sort of physical document, you are covered under seller protection (i.e. ship a btc address and then an email to confirm receipt of the document). Is this true?
I don't know anything about that. Sorry.
-What are some of the best options (both safe and timely) to sell BTC and make a profit?
Buy when it's cheap, sell when it's up.
There are no good options to make a quick profit on Bitcoin trading.
Best regards.