ANY capital expenditure like HVAC or a roof could take years to make up and with no way to sell because you're close to full value. 

Some expenditures have to be capitalized, like major improvements. 

there are a couple "rules of thumb" that people use around here.1. mortgage payment should be half of rent2. rent should be between 1 and 2% of home value3. subtract 10% of rent for vacancy, 10% for capital expenditures, and 10% for management fees (basically subtract 30% from rent, but the 3 numbers vary by location) and the difference between that number and mortgage is your cash flowthese are very broad heuristics that vary wildly by market though. if you are interested in learning about real estate investing, spend a lot of time reading these forums and podcasts. you can learn a lot here.

Here is what I was looking at for the breakdown.Purchase price - 153,000.00 Financing - 122,400.00 at 4.5% for 30 years = 620.00 per month20% Down payment (HELOC) - 30,600.00 at 5% for 10 years = 325.00 per monthRent (Quick look) - 1,200.00 per monthTaxes - (On the website it says 630.00 but on the county website it has a formula with [Tax assessment value x Assessment rate (currently 7.96%) x Mill levy (last year was .088) which turns out to be 153,000 x .0796 x .088 = 1071.73 per year.] 1071.73 / 12 months = 89.31Insurance - (Quick Google search for average) 106.00 per monthVacancy Allowance - (Reading BP says factor 5%-15% so I am going with 10%) 120.00 per monthRepair Allowance - (Reading BP says factor 5%-15% so I am going with 10%) 120.00 per month Capital Expenditures - (Reading BP says factor 5%-15% so I am going with 10%) 120.00 per monthProperty Management - (Usually around 8%-12% so I am going with 10%) 120.00 per monthIn this I am assuming that the tenant pays all utilities and yard maintenance so that isn't factored in.So.... 89.31+106.00+120.00+120.00+120.00+120.00= 675.31 Total So all that added up is....620.00+325.00+675.31= 1620.31 per month420.31 over the 1200.00 rent I know the deal won't work on this one I am just looking at my math to make sure I am factoring everything and just trying to start practicing.

I cannot speak to other lenders but for us we do not take into account previous capital expenditures if they are one time or upgrades.

If you're making $1,200 annually then you'll have a harder time selling it for anything worthwhile.I'm assuming your calculation includes maintenance, but does it include building up reserves for capital expenditures like a new roof?

You are not taking into consideration other factors...Your $1,500 a month - $1,200 Mortgage (taxes and PMI) = $300 is correct.But you can always assume Capital Expenditures and Repairs (I do 10% each) and Vacancy (I do 5%).So with that amount, you are look at $300 for repairs alone, taking your Cashflow to -0-, then if you set aside the 5% ($75) for vacancy you are in the negative.And that isn't even taking into consideration an additional estimated 10% for property management (Because you might not always want to manage your own properties).I would say to 1031 exchange that into something with more cash flow potential for you.

If it is within reasonable vacinity of the entertainment parks and attractions, several units could be rented as vacation rentals which would bring higher income, but also higher time expenditure for management. 

I've found only disadvantages associated with acquiring older Multi-Family units....More Wear-and-tear, expensive capital expenditures regarding roof replacement, higher insurance, etc...

In general, my analysis seeks a minimum 5 percent cap rate, utilizing 10 percent for vacancy losses, and 8 percent for each management, repairs, and capital expenditures.