Let them pay for what they use and they'll waste less. 

They don't care what the "real" value is and so paying for an appraisal is a waste.

I wasted so much time and effort with previous agents.

What are the potential pitfalls to this other than the obvious such as, I buy a lemon and waste a ton of my 401k money. 

Most banks won't do this small of a park so you'll want to start having that conversation with the seller about seller financing now before you waste too much of your time.  

That would open the wall in the kitchen to enable another cabinet but it would at least make the living area seem less consumed by the fireplace and would make it more modern looking which would make your appraisal come out a little better when you refi and would help you get better tenants because it would look more attractive.

Reminds me of a guy years ago that built a car in his basement then realized it was in a basement, had to have a hole cut in the wall to get it out.

Your SOL my friend, Brit has a good point there keep them in the unit smoke damage only really goes so far.Keep them long term and then bleach and paint all the walls when they leave install some new flooring if you have any carpet.Next time it's for rent the best way to determine a smoker, Ask to see the inside of the car they drive or their finger tips:-).

With the information you've given so far I would say send letters to every address you have.If it's a bank or mortgage servicing company and it's a large one, don't waste money on stamps.If it's a local bank, like HI only, go to a branch and ask for the REO dept.Good luck!

If you have no intention on listing the house instead of wasting an agents time with a fake listing appointment you could hire a realtor to do a BPO (Broker Price Opinion) which should only cost about $50 and should provide you with enough information to see if the appraiser was way off.