The path does not show up on any documents in the public record but a survey would show the path as an access to your property and would hopefully trigger an investigation as to what it is and why it is there.

There have been some preliminary tests by an oil & gas company in the area and I guess there's a possibility he has oil.

I would definitely pressure people to fill out an application on the spot for me to review and be able to offer them a preliminary approval pending payment for and results of the background check.  

I know what you mean for finding deals, a lot of time is spent investigating properties and researching.

I would say most people gloss over this sentence, but this seems like something worth investigating...

If no complaint was issued inform the animal control officer of the dog bite incident and say you want it investigated.

Do some investigation first with the city.

Instead of relying on a real estate agent to bring them potential fitting homes to investigate, buyers are able to do much more homework on their own and only use the agent for guidance when needed.

I also did my little investigation and turned out it is $423 for water, $564 for sewer for last year. 

Also, if you give your title company or broker a call, they should provide you with a preliminary closing statement which will show your closing costs, almost to the penny to help ease your mind.