The purchase price is $325,000, and as part of an end-of-year incentive, DR Horton bought the interest rate down to 3.99%.

I couldn’t tell you what rates are today but I assume they are competitive.

Hopefully as the rates and the housing market loosens so will some of these guidelines in the HML programs. from talking to hard money funds especially those who operate in more than 10 states, and 5 years of experience with underwriting teams, I'd actually disagree and say new construction is preferred to rehab due to experience level to enter the market. there's BP lenders that will do 15% LTC with 1-2 new build experience.

There are some markets here growing at rapid rates. 

Your insurance is going to be highly variable and I wouldn't use what an agent or the seller tells you as the cost of dwelling policies have increased substantially over the past few years due to rising new construction costs. 

The more you pull out the higher the rate.

I am locked into a 30-year loan with a 2.8% interest rate, so refinancing doesn't make sense given the current high-interest rates.

I’d suggest you call a PM or two and ask them 1) How much rent they would charge. 2) What fees they would charge you. 3) How long they think it would take to find a tenant at that rate.

The demand for market rate is good.

Deduct NEW property taxes after you buyDeduct home insurance costsDeduct maintenance percentage, typically 10%Deduct vacancy+tenant nonperformance percentage(we recommend 5% for Class A, 10% Class B, 20% Class C, good luck with Class D)Deduct whatever dollar/percentage of cashflow you wantNow, what you have left over is the amount for debt service.Enter it into a mortgage calculator, with current interest rate for an investment property, to determine your maximum mortgage amount.Divide the mortgage amount by either 75% or 80%, depending on the required down payment percentage - this is your tentative price to offer.If the property needs repairs, you'll want to deduct 110%-120% of the estimated repairs from this amount.Be sure to also research the ARV and make sure it's 10-20% higher than your tentative purchase price.As long as the ARV checks out, this is the purchase price to offer.It is probably significantly below the asking price.