Inwood is nice, but you have to go through crappy neighbohoods like Washington Heights to get there.
If you caught an express A train you would get to Inwood in 20 minutes, or 40 minutes from downtown Manhattan or the Village if you caught a local train instead.
It would help if you told us what you could afford on rent per momth. So many people want to live in Manhattan only to discover they can't afford to live in Manhattan.
The person using the living room as a bedroom would have to deal with people walking through to get to the other bedroom.
You should read this thread...
//www.city-data.com/forum/new-y...ttan-stay.html
Even if your stay isn't short, the answers still apply.