Evaluate this Townhouse as well as the HOA concept

We had an offer accepted the other day on a townhouse listed at 45k. It was fully flipped just a couple of years ago and the inside is in great shape. We would be buying from the owner who bought the flip and have had to move out of state. We offered 42.5 and seller will be paying 2 percent of closing costs. The downsides are the furnace is 30 years old and will need to be replaced soon and the roof appears to be in pretty bad shape. But other than the new furnace other costs will be minimal. First, what are the due diligence aspects of buying a place with an HOA?

Here are some other numbers.

Purchase Price $42.500

Mortgage $190

Vacancy $68

Cleaning and Maint $45 Is this low? Made it less than my sfh.

Insurance $42

PM $85

Taxes $46

HOA fees $150.00

Rent $850 figured a bit low

Comes out to a cash flow of $224