I would start off by getting several quotes.I can tell you that my regular AC guy charges 40% more than the guy I go with.  

It looks like your seller wants to seller finance the deal to 'be the bank' - which can be great - maybe you can negotiate a better deal on interest rates than what is currently going on in the regular market - which would be awesome.As for which home first - I would definitely go for the duplex you are already in.  

I invest regularly in Worcester, Providence, and towns outside of Worcester. 

Banks do this regularly during any kind of financial hiccup.  

That will help keep thing square with the guests.Remember that you need to do a full background check etc etc with a regular full lease for the time they are there.

I have been doing that since September.The resort is beautiful and the proximity to Disney is great.For someone that wants to travel to the parks on a regular basis owning in Margaritaville is perfect. 

Whether it was regular depreciation or bonus depreciation from cost segregation - same treatment basically: no immediate tax consequences. 

If you do that, it goes on Schedule E like a regular rental, but the difference is that the tax loss isn't limited by the passive activity rules on form 8582.

I'd like to invest back home in Ohio eventually (I lived in both Columbus and Dayton for about 5 years each), but I'm much more comfortable starting with something I can see regularly. 

You might want to listen to some of the BP podcasts on some of the other ways that real estate "pays" you, outside of cashflow.Keith Weinhold from Get Rich Education also has a good podcast and regularly discusses the 5 different ways that real estate pays you.