Sure but need more details on just what you are trying to do and what role you are playing.  

I'm researching property management companies in the area that I'm interested in investing in, and one of the property managers I talked to said that he's also a real estate agent, and would like to help me buy a house in addition to managing the house.Is this dual-role situation common?

The snow may play a minor role in finding a tenant this time of year but nothing significant. 

if it were me, i would put the new trailer in. i'd offer it to the upper end of the blue collars as RTO/LP. whether they exercise the right to buy or not, the "new-ness" can command a higher monthly rent/payment. if you can find someone to put a sizable down payment proving intent on ownership, they ought to treat the property better.3rd option, just offer the lot for rent at $300-$400/mo. they can bring their own trailer. if they ever leave, it should be in the lease that if they leave the home on the lot more than 30 days beyond their move-out date, the trailer becomes your. for free. clean it up and rent it out again. save yourself from spending 30k up front.just make sure your Monthly rent - PITI = cash flow. 

Size, rooms/bath, garage, year built are just some examples of what you use to find like properties.Practice makes perfect and this exercise will also increase your knowledge in each neighborhood.

That's the amount you would be willing to invest today to get those dollar amounts at the end of each of those 5 years.So basically in the above exercise you had the future cash flows and the discount rate and from that you calculated the Present Value.

I'll chime in briefly, then take my leave.The method of payment for the purchase (cash out, RE Contract, DofT) when exercised will be outlined in the Option only.  

Lastly, as a realtor and an attorney who focuses on real estate I can assure you that the Seller's attorney, NOT THE REALTOR, who has any role with the title company. 

Our people are all bonded and insured and in 15 years i only had once complaint of theft, for something that was found later by the tenant in their son's room.You have to exercise control, but in compliance to the lease and codes.

You will have to make a nonrefundable deposit, but it's much less than a down payment, and will count as one if you exercise your option.