The rent to value is simply far too low.Sell it.With 500-600K in equity, mortgages at 5% and opportunity value of cash in the conservative range of 10% you are presently losing $2000 - $2500/month on your dead equity alone. 

Assuming the OP and his partners are active investors that is..... and that they are not going broke....Why not save this to have in stock, awaiting the next slab house they buy?

Almost any asset could be short-term, but they’re commonly stocks, high-yield savings accounts, corporate bond funds, treasury bills, or money market accounts.

@Gino Barbaro is dead on when he pointed out above, this is a different era and the CAP rates have remained compressed longer than most MF investors have expected due to three factors 1)Downsizing Baby Boomers, 2) Gen X/Millennnials delaying the purchase of a house, and the rapid growth of migrant population coming from countries where home ownership is not even a possibility for most. 

Any build up I am not saving for, typically goes into the stock market.

Then check the property to make sure she is not dead inside.

Just stock the 5 gallon buckets in your garage, shake em and go. 

Some has to do with what you think the stock market will be doing between now and retirement.if you are filing married joint return with a taxable income under $315,000 from all sources, then you are probably "ok" for fairly "simple" tax reporting and not a lot has changed except you will be paying a lot less in taxes.

@David Smit and @Mike Reynolds, i spread it two days ago so i'm hoping any and all squatters are dead and can be swept away, thanks for the responsesI found out the hard way about the need for a respirator, should have read the directions.Hoping to sweep up today and start painting several rooms.

The lawn was dead, so we are doing a native Ca plant yard, with fence to set off a little patio area in front...