Buyer wants to delay sale

[Billy Rogers]

I have a piece of land for sale for $6,200.    I had a buyer offer $5,000 cash and wanted to close tomorrow so I agreed to the sale.   

Another potential buyer I had talked to earlier called today and said he had the cash and wanted to buy the property.  I told him I had already accepted another offer but would contact him if the sale fell through.

The guy I made the deal with called today and said he plans to put a mobile home on the property and the company financing the mobile home wants to put the land in with the mobile home loan and pay me when he closes on the mobile home.  He said he doesn't know when that will be, but he will let me know on Tuesday.

What should I do?   The first guy is a really nice young guy, but part of me thinks that the deal was to close for cash on sunday for $5k and now there's an undefined delay.   Should I contact the second guy?  He didn't even try to negotiate on the price and said he has the cash.  Should I tell the first guy that I need to be compensated for the delay?

I know it's easy for people on the internet to say forget the first guy take the higher amount from the second guy when they aren't in this situation, so please give me some seriously thought out answers.   I'm wanting to build my business to a high ethical standard.