You might consider giving a notice to the entire building that you will be doing a walk-through on a certain date to check the condition of the property - you have a right to maintain your property and access all units if they are home or not with proper notice.Also, make sure that your notices have a person named as UNKNOWN OCCUPANTS listed.

What are the most promising alternative lending strategies for financing RE developments given the rising interest rates and tightening credit conditions?

The condition, age, and future capex issues are more important in my opinion.

Keep focused on your goals and keep in mind it will take longer to build enough wealth because the conditions of the next 5 years in real estate will be much different than the last 5-10 when many people made their money. 

We recognized market conditions were optimal for a fast flip, and our ability to act quickly minimized holding costs while maximizing profit.

It was priced at $105K.... in fair/poor condition... it was still an amazing deal. 

You are starting to hear the more conservative approach more often with the current economic conditions. 

Though, if you want to make changes with newer mobile homes there may be some restrictions (i.e. age, condition, etc.).

Anyway, after appraisal we were able to insured the property with Universal company, I recently got a letter that my policy was going to be cancelled due to the condition of the roof.

If you are looking for an investment it is very helpful to know from the numbers perspective of what you are looking for, strategy, what type of areas you are looking in, condition of the property/how much work you are comfortable with, etc.