moving a future business to another state

I am in the planning stages of my business.  I plan to start actually doing business for profit within the next 2-5 years.  I will be the sole business owner, but there will be two parts to my business-- one part will be a berry farm and the other part, which I will develop when the berry farm has been up and running for a few years, will be a wellness center on the farm premises.  I want to register my desired business name(s) now, and on a national level, because I want to reserve those names.  Also, I know I will be moving to a different state next year (though I don't know which one), and I want to make sure I will be able to keep my same business names no matter which state I move to.   I have a few questions and would very much appreciate your replies:

1) Though I will not be having a location for my business for a few years still, I want to create interest in my future business, so I may hold some activities in my community to draw interest and practice my skills.  I would do this right now.  I was thinking to avoid problems with liability, I should register as an LLC.  Any comments on this?

2) How should I go about figuring out if I should form 1 LLC for both parts of the business or if I should form 2 seperate LLC's, one for the farm and one for the wellness center?  I want taxes and other paperwork to be as simple as possible, but I want two seperate names, and I will be promoting two different types of products to two distinct markets.

3)  From what I have read, it sounds like I should register my business(es) as Trade Names to reserve those names on a national level.  Does this mean I should register my 1 or 2 businesses with my state AND file for these Trade Names on a National Level?  Or can I just go straight to the national level somehow?

4)  What happens if I only register my business on a state level, not on a national level, and I move to a new state and someone else in that state has now started a business with my same name?  Does that mean I am out of luck, or is there some way to keep the former state's registration and continue operating business under my original business name, even though I now conduct business in a new state? 

Thank you in advance for your responses,

Heally9