I would like to try to put together an option to purchase the property as is, of course after doing all the proper due diligence. ( I suspect that much of the electrical and plumbing is shot...lots of work to bring it up, but it could be a beautiful place) Can anyone point me to a basic investor formula to evaluate a reasonable offer for this type of property as is, and determine what the percentage and length of an option should be?  

From this data, you can utilize a website bestplaces.net that will give you a breakdown of the percentage of homes that sold, in various price ranges, for a given zip code.

For those of you who rent out properties, what percentage of the time would you say you're dealing with a good tenant versus a bad one?

While your insurance and mortgage payments may have a variable rate of cost proportional to your home value, certain repair costs will have a more fixed rate cost, and thus decrease as a percentage of the home value as that value goes up.

For a percentage stand point, what is average, what is good, and what is amazing. 

I try to focus on end user areas with a high percentage of cash sales.

Negotiate a percentage profit split.

FACT:  The percentage of qualified homebuyers is the lowest it's been since the 1960's. 

The low rent would probably cause a PM to ask a a high percentage of your rent, which is another hit.

Percentage commissions won't cut it for you, though.