Most property management companies charge anywhere between 10-35% of your gross revenue.

That places your renewal during warmer months when you can charge higher rents. 

If you find a great deal and can still receive decent returns after common charges/maintenance/HOA fees, I don't see why not. 

Most closing costs are not actually charged by the lender.

When dealing with Hard Money steer clear of anyone trying to charge an upfront fee while promising you terms that far exceed everyone else you talked to.

Here is a list of due diligence item I use on my MHP investments:Check zoning and permitting compliance (city zoning)Check local law compliance (with Sherriff and/or Police)Search City Council minutes for any adverse mentionsCheck with State Department of Public Health's Division of Community Environmental Protection (CEP) for compliance violationsCheck with property neighbors for any disputes or pending legal actions Water - Check with water provider for any open or recent issuesSewer - Check with Sewer provider for any open or recent issues or complaintsElectricity - Check with electricity provider for any open or recent issues Rent roll with space number, name of resident, move-in date, renter or owner occupied, number of occupants, monthly rent, additional charges, current balance due and any relevant notes about the residentList of capital expenditures for the last 3 yearsGet last 2 years of Profit and Loss statementsGet last 2 years of Tax Returns for the LLC/Park12 months of Bank Statements for the LLC/ParkCurrent Accounts receivable statementsBuild proforma for next 5 years using rent roll and expensesGet owed taxes to City/County/Local govGet Insurance Quote of commercial liability insurance2 years of utility billsProperty Tax bills for last 2 years List of park owned home including copies of “rent to own” or sales contractsGet list of vendors and contract status for each vendorTalk with on-site property manager regarding issuesConduct Onsite Property Visit with property managerSpreadsheet detailing who pays all utilities including water, sewer, gas, electric, trash, cable, etc.

for the sake of analysis I used $250/month for water and $700/ annually for insurance.Since the water is not separately metered, can I charge the tenants a small fee for water?

Pros you can charge a bit more and tenants don't need to supply their own. 

Because you mentioned managers, I am assuming you didn't use a service like fundrise.But, you can't estimate profit without estimating what your estimated revenue will be and subtracting all the costs.I.e, how much longer does the roof have, what portion of the rent is being budgeted for future repairs, who covers the cost of repairs, how does the tenant request repairs, what are all the expected monthly expenses, how much is the management team charging you, how do you know the management team is doing their job, what are the names of the contracting companies they are using if they are constructing the property.

We typically look to the local market and its comps to justify what rents we can charge for new occupancy and renewals.