What are the deferred maintenance items?

Is it possible to renegotiate the offers for a deferred closing?

For the replacement reserve (if it exists) maybe something like this can be inserted (but consult your attorney)Seller agrees to provide Buyer with a credit at closing for deferred maintenance in an amount equal to the balance of the Seller’s reserve for replacements account that was established in accordance with the terms of the Seller’s mortgage.

I will guess that with a sale price of $650,000 your taxable gain is well below the $500,000 level, so it should be all tax deferred with the except of one year of depreciation recapture, which is not a huge issue. 

Sounds like you may be ready for passing it on,too.Unfortunately, these properties sell all the time, often to new owners not fully aware of the deferred CAP EX and replacements costs.

Owning it in an LLC on a land contract may limit you to needing a commercial loan to buyout the balloon payment, unless you transfer it back to yourselves personally to get the refinance done.I typically budget $500 per unit in repairs assuming that the property will have no deferred maintenance and looks good to attract the right tenants.If you are buying it on a land contract you wouldn't have any PMI, so that is an expense you can take out.Otherwise the play may be to owner occupy one of the units.

So instead of making new contributions to a tax-deferred account such as IRA you should invest under your own name (or entity that you own).

You have an asset that is performing well and all of the deferred maintenance has been taken care of.

 @Daniel Delanty:Income or gains generated by a 401(k) Plan generate tax-deferred/tax-free profits.

You just can't have boot if you want to defer all taxation on the sale of your current prop.