Trailering do's and don'ts?

I'm trailering my duo to Kentucky come September and I was told to use uship.com to find a hauler to move them. What's some of the things I should ask and look for when going through the different people to find the one that I'll eventually use to move my two?
I know I posted already that the two are calm, quiet and older(16 and 24), I also know it's around 1,000 miles. I know to look at their feedback/references and see what the others have to say about their experience. A few of the ones I looked into have layover spots, while others have mulitiple drivers all with a lot of horse care experience. Some fo them have box stall trailers while some are the typical show horsie trailers(slant load, long, air suspension, cushy). Most of them stop every few hours to let the horses off to stretch their legs and drink, this I do like. Some also offer to feed them while en-route if necessary, but I would only do that If the grain is pre-measured in ziplocks so I know they're getting what they are used to.
The longest that I have ever had to trailer a horse was 5 hours, and that was to bring Phoenix home. My dad was driving this, since it was his truck and I have never driven with a trailer before. This is 16 hours straight through by car(I've driven it with my dad before).
I am kind of nervous about doing this, actually I'm scared to death, but I don't/won't leave them behind.
Anybody ever had to deal with this before? My only other option if I can't find a hauler that I like is to take my aunt Lisa's trailer(Small two horse straight load) and bring them down myself. But that scares me even more, than letting a commerical hauler take them.
My only other thought is to go down to the race track in Saratoga and see if anyone is sending an empty truck to Churchill downs and see what they'd charge me to bring two horses down to Churchill Downs and pick them up from there with my Aunts Trailer, she's only an hourish away from Churchill Downs. Help??