About to take the plunge! Questions!

So I've been in and out of call center type jobs and low paying retail since 2009. I'm 26 years old and I live in Tucson AZ and I want to get the neck outta here. I have a few thousand dollars in debt but nothing that's holding me back, and things have been pretty rocky with the girlfriend lately so that might be on its last leg... I'm renting a room in my friends house so I'm not on the lease and I don't really have my own car at the moment. I have a perfectly valid license but I've had a couple camera tickets and one driving without insurance that's maybe 3 years old. But EVERYTHING has been paid in full and I think those things have dropped from my record. So my questions are:
-What company/ies is/are widely accepted as the best company to drive for if I also need them to pay for my CDL?
-If I'm single, have no expenses besides a phone bill, the costs to drive the truck, and living costs OTR, will I be able to bank a decent little cushion if I run hard for 2-3 years?
-I'm 6'4"... am I gonna have issues in the truck? And also, how nice are the trucks that are given to company newbies and will they have inverters? (Not important just curious)
-Im used to making like 500-700 dollar checks every 2 weeks... If if its just me and my minimal expenses, will I be happy even at the low end of the pay spectrum?
-ANY other tips/things you wish you knew would be very much appreciated!!! THANKS!!!

 

Yeah I've seen a few people talk about them in the forums and they sound great. Would it be an obstacle to get to them from Tucson AZ or would they help with that?

 

Awesome congrats! Is it that they are filling their spots really quickly? If I cant get on with them is there a next best?

 

Isn't Prime considered ones of the "Mega's" ? I heard you should avoid the huge national companies at all costs...

 

Would you say in that order or are those all good starting companies? And will they all pay for CDL?