update -- I read $500,000 price which is not a steal but seems reasonable -- Obviously $250k price is different story. Much better.
~$25k per space at $295 lot rent is about 85x gross. Your expense ratio will make-or-break the deal -- get a very good handle on what the expenses will be for the way you will run the park.
Run the numbers again the way you think you will manage the park -- and you ought to have at least some vacancy or you can raise the rents until you do.
You state gross 75000 which is $6250 per month.
You also state $295 lot rent and 20 (or 21?) lots rented; plus (or including?) an apartment.
$295 times 20 lots is only $5900 -- so that's $350 per month that you have to account for.
Do you mean manager gets $35 discount on rent or $260 discount?
You cannot include the apartment rent as though it were lot rent. In any case, I would assume a manager can live in the apartment for free or you'll be paying a manager in some other form. What are your other expenses (taxes, maintenance -- don't forget this!, insurance, some other stuff, etc).
Assuming you run the park this way (manager in apartment), I would run the numbers assuming something less than 100% occupancy -- 5-10% vacancy is not unreasonable which is 1-2 lots for you.
In any case, it's all hand-waving at this point so figure proposed purchase $500k for the park at $6000 gross per month and it is already financed at 8% rate 50% LTV. That's not great financing so count on doing better with a bank, but it's flexible so that is better. If you can find a bank.
(A) Either you'll have to cough up $250k (or a little more for startup -- call it $300k) and you'll be paying $2,390 per month in P&I. Count on your gross being a little less than $6,000 as previously calculated. If your expense ratio is near 50%, you'll be seeing $3,000 in expenses leaving you with about $600 monthly in profit (plus mortgage paydown) on your investment of $250,000. (or $300,000, or whatever). That's a cash-on-cash return of less than 3% plus mortgage paydown, which is part of your capital gain. Plus whatever capital gain, which is protected (hedged) against inflation because you can reset your income commensurate with the pace of inflation and take on debt which is long-term fixed.
Is that an acceptable gain for the risk you've allocated (risk of not "making" a 50% expense ratio plus risk of anything else not being right in my analysis?)
(B) At 30% expense ratio (through your superior management) you'll be seeing expenses of $2,400 (P&I) plus $1800 (30% of $6,000 gross) leaving $1800 monthly in profit which is 8.6% cash-on-cash, which is a heck of a lot better than you could count on in practically any other investment with a relatively low risk profile.
Can you keep your expenses down to this level? Is that a risk you are willing to take?
(C) If you can refi at 30% down, 6% rate on 20-year amort, you'll have $150,000 in the enterprise and P&I of about $100 more per month. Assuming a 40% in-between expense ratio you'll have $2400 per month in expenses, $2500 per month of P&I total of $4,900 from $6,000 gross, leaving $1,100 per month profit on $150,000 investment. That's 8.8% cash-on-cash with fairly conservative numbers.
(D) I made up my numbers from your numbers. It's your job to get the "right" numbers during DD.