I am hoping to reserve my capital for the addition of homes and overall improvement of the park.

Though I have no interest in the transactional job of real estate, these sort of things (doing management, easy access to properties on the market) make getting my license more and more attractive on a practical level.

One common rule of thumb is to take 80% of the purchase price for improvements and 20% for land.Another way to do it is to look at the county's values for both land and improvements and use those to determine the percentage. 

What I did is put stuff in garage for a month and discount rent for new tenant by $50 for first month to compensate for no access to garage.

If the buyer has access to other sources of cheap capital, lender will probably have to be happy with the lower end of your range. 

You would then be required to calculate the depreciation expense.Depending on if the cost is for a repair or an improvement will determine if its currently expensed or capitalized.

The contractor should have access to roofers, framers, concrete, pool, plumbers, electrical, tile, sheetrock, kitchen & bathroom installers, painters etc and should pull the permits.

Sadly I don't have access to the MLS system, so I can't pull actual comps yet. 

Do you have access to deal?

What’s unique is that the basement only has an exterior entrance so if I added rooms to the basement, they would essentially need to walk outside to have access to kitchen/bath/laundry.