Calculating cap rate on co-op rental - what expenses to include? what property value?

So I am trying to calculate the cap rate on my co-op. I moved out and am renting it out for the next year while I decide next moves.

First question is how do I calculate the NOI going into my cap rate? My rental income is $54,000 a year. I pay maintenance of $14,000 a year. And then my mortgage is $24,000 a year (3-4% rate). Do I take $54K - $14K for my NOI, are there other 'levered NOI' calcs to account for my mortgage?

Second question is valuation of property....I bought the property for around $500K and put in $50K of renovations. Is that the number I use, or it the current valuation which has a relatively wide range from $600-750K.

I think this would all imply a 5-6% cap rate which seems decent, but not exactly sure the other considerations that go into this? Do you also account for the potential appreciation of a property (3% a year maybe?).