If this quote gives you the option to lock your rate until the expected closing this fall, the long lock could be contributing to the high cost.  

I don't spend anywhere near that much time.Personally, I would forgo all partners and move forward on my own if it was an option.

Now, consider your options – developing the entire 5 acres is ambitious and requires substantial investment and expertise.

You need to understand the options OR have someone assisting you who does!

If you find that you aren't up for active real estate investing there are passive options to invest by partnering with an active experienced investor, investing in a syndication as a limited partner, etc. 

One option for funding might be just a personal loan from a local bank or credit union.

For the refinance you might want to consider options other than hard money. 

If young and willing to take risk, renting is an option.

The reasons for either option are obvious.

You might be able to find a duplex in the older areas to house hack if that's an option for you.