First way to approach this is to look at the cost of money from your different sources.  

Is this how I should approach this?

If you do not want to put up application fee then there is no further action.Before you approach a lender find out all their requirements and terms first.

It sounds pretty straight forward but is there anything to be particularly cautious of when approaching these kinds of deals?

I have tried a couple of approaches but can't seem to nail the correct message.I based my design and message on a sample postcard I posted here in BP that had good success as per the user.Below is the landing page screenshot.

I need to get this down so I can analyze any wholesale, flip, or buy and hold deals I come across.What approach do I take?

It depends on your approach...

If so I would consider approaching the Eng Dept at a local college or University for a class exercise estimate. 

This also assumes the Park is on city water and sewer and not well and septic...As far as the stick home goes you should seek to purchase the property without it, but if you have to acquire it then yes using comps is the correct approach.  

But one commercial deal can make your whole year.I was approached by a group wanting to buy a hotel in the Houston area.