Each neighborhood can also vary considerably.

This will vary from Bank to bank, really.

In the research I've done on Sub2 deals (which led me to conclude it's not the right strategy for me, but your mileage may vary) there is Federal Law pertaining to "Fraudulent Concealment" - and the potential of having a 'Due on Sale' clause triggered is much less worrying to me than committing a felony.

For example, even in the same location, insurance can vary widely based on age, sex, the company involved, any past claims, deductibles, etc etc.

And does it vary by state or mostly by county?

You should seek counsel from your own attorney before taking any action based on information found in a forum online as the actual facts of the situation and issues may vary.

As you can see it will vary from state to state, so when you get to google make sure to type something like "Florida State agency real estate"  rather than "how to get my Florida Real Estate license" as this will probably yield a ton of websites trying to sell you the pre license course.  

As to the design, often varying designs add character.

Laws vary state to state and you have to make sure that you properly maintain an entitiy in order to receive all of the benefits/protection.That being said, most investors put properties in an LLC.

The cost to renovate a mobile home can vary, but $5,000 can buy you a lot on one of these homes.