Wanting back in the flatbed game

I'm about as tired of this doorslamming gig as I can get. I'm making OK money right now, but if I was happy with 'OK' money, I would've stayed a company driver.

I'd like some advice from the old grizzled ones. I'll lay out my tentative plans here & let you guys poke holes in them so I don't make too many mistakes when I start laying down my cash for equipment & wave bye-bye to docks & door times.

First, I'm looking at four companies to lease on with. In no particular order:

Bennett Motor Express
Mercer Transportation
Admiral Merchants
Greentree Transportation

I was originally all gung-ho about getting an RGN & getting back into OD & heavy haul, but after talking with a lot of people, I've decided I like the LTL deal a lot better. Less headaches, less stress, less overhead.
Any thoughts you guys have on these companies would be greatly appreciated.

Now on to equipment. I'll be keeping the T2 in my sig for a while, as she's been good to me so far. I need to get a good trailer.
I can go a few different routes here, and want to hear your take on them.

1. Flat or stepdeck
2. All Aluminum or composite
3. new or used
4. 48x102, 53x102, or some variation in between

My gut reaction is to go used, get a decent 48x102 aluminum flat as cheap as I can & go to the races. The truck is kinda heavy (21,500 w/ full tanks, me and my stuff on board), so I expect with a headache rack, chains, binders & tarps, I'll probably be closer to 23k. I'm thinking lightweight is gonna be a good thing when I buy a trailer.
But when I start looking at used trailers, I really wonder what I should be looking for... What's going to really be a necessity, and what's just fluff? What's too old? What do I really need to avoid? Am I just asking for trouble going used instead of just buying new & getting what I want from the get go?
Those of you who have dealt with all this before, asked all those questions, and started a lot of thoughts with "Next time I'm gonna get...", please help me make some good choices & avoid some pitfalls.

 

Appreciate the input, fortycalglock. I was kind of feeling the same way about used flat prices. I'm a little skittish about buying a three axle. Don't really think this truck's specs would handle a lot of heavy loads like that without busting at the seams sooner or later. I could be wrong, just don't want to get in over my head.

 

Thanks for the info, aiwiron. Any recommendations on companies?