I would reinvest in a another property and use a 1031 exchange to detour taxes.   

.: My first investment property happens to be my first home purchase, so my questions are hopefully basic for anyone experienced here.

So, how much and whether it makes sense to update a property is about making it cash-flow better as a rental NOT ARV. 

I have owned this property for 8 years, 7 as a rental property.

You want to know of any & all problems before spending any additional funds on the property!

NYC property values are increasing at or above the national average (4%).

. $50k land value on a $600k property sounds very low / possibly incorrect 2.

Only the PMC is continuously connected with you until you sell the property.

Try to make a goal of buying 1-2 properties each year.

Unfortunately, this reassessment is unavoidable, so you’ll need to evaluate whether transferring the property is worth the potential tax increase.If a Transfer Is Not Feasible:If the potential property tax increase makes the transfer impractical, an alternative option is for your father-in-law to secure a Home Equity Line of Credit (HELOC) on the property.