The mortgage is $1400 and the house is worth $250k.I did tell him if it is okay for him,I could take up the mortgage and he says he would get back to me as he also as a brother and uncles to talk with.The house is close to my work place as well.Please, does anyone has a thought on this?

That’s what really makes you happy.A good workplace doesn't happen fast.So, what does a good workplace have?

Luckily our tenant is easy going. his entrance has a different front door but not his own house number. 

After diligent searching there are ZERO duplexes for sale within an hours drive of my work place.

I do think you need a separate entrance option or at least two entrances in a four-plex to make it easier on the LTR tenants, but if you are open about it form the start, everyone gets it and you choose the unit composition based on which ones will be STR or MTR.

I'll include all details below.THE LOCATION: The hotel is conveniently located in the breathtaking Smoky Mountains, just minutes away from the Great Smoky Mountain NP entrance.

Like @Russell Brazil said there are general things that need to be in place.One that stings a lot of people is the main entrance door.

Does the side unit have a separate entrance like a mother-daughter? 

Is there a private entrance/parking or room to make one?

Look for multis with separate entrances in different areas like one door in front for one unit and a door on the side or back for another.