My question is, do I make the offer and seal up the deal, then find the cash for the renovation? 

But what if they don't repair the roof, stripe and seal the parking lot or just plain don't sweep up.

Does the roof need to be replaced or can it be patched/sealed?

Update paperwork with the seller to seal in your deal and give them more time.

Any advice from those in the know, as to the paperwork to use when sealing the deal on an owner financed purchase on a free& clear property?

We put water,sewer,and trash into the lease to make sure it is paid and not under the tenants control.So we will have base rent plus these utilities listed in the rent for a total rent price.Fulton county is one of the few counties in Georgia where a water lien SURVIVES foreclosure.No way to get rid of it except through the local council person with legislation or negotiating a payoff of the lien.With our apartment units the benefit is we get the bill so we can moniter water usage.If the bill is really large you can use a water leak adjustment form with the Fulton county water authority.Depending on the age of your property pay special attention to leaky faucets and old toilets leaking at the wax seal,the return line,and or the tank into the bowl.If you have plumbing leaks anywhere it will drive the water bill up.If you have an outside water spigot get it capped off or removed.Tenants are notorious for using water outside and driving the bill up.You better get a hold of this lien issue now or it will get worse.

ozone machine, fresh paint and these.. http://www.amazon.com/Big-Fire-After-Aerosol-Fogge...Put a few of these in your house and it will kill most of the odors, if it is pet odor in the carpet the only real way to kill that is new carpet and padding and sometimes if it is bad enough have to seal the floor under the carpet

In many states Death Certificates are private and sealed by law. 

Check manufacturer’s specifications and association manuals for the correct placement of nails across the length of the shingle.8.Over Driven Fasteners: Fasteners that have been over driven require the sealing of the over driven fastener head and adding a new properly placed and driven fastener.9.Mansard Roof Shingle Fastening: Mansard roof applications also require the butts of all asphalt shingles to be hand sealed down in addition to six nails for each shingle per the Asphalt Manufacturer's Association Manual.

Air in the system can cause cold radiators but you said you had the system bled so that shouldnt be an issue any longer so I would take the seal up approach and work from there.