Have to go along with Night. I never wait 10 min. in Laredo unless I am the only truck. I first check the Houston board and if it is light I can be on the board in 5 hours. We get loads out of Laredo every day but we have many more trucks inbound then outbound.
The carrier you are with makes a big difference also. Panther works on flat rate so the load out of Laredo pays the same per mile as a load out of Houston, I Think? Correct me if I am wrong.
As far as FECC I find the rates to run 30-40c a mile higher out of Houston, so anything over 1000 miles would easily make up for the 350 mile d/h from Laredo, even if you did it for free.
I would first try calling planning for a relocation load at 50-70c a mile if not that, then authorized d/h at the 35c and if not authorized I just go anyway.
As far as Dallas, the trouble there is the 10 or so LG loads every day. Most are under 500 miles and go west or south.
A Sunday noon check of the express centers shows no C or D's in Laredo, San Antonio or Harlingen. So staying in Laredo you would probably get out Monday. The Dallas board is showing 2 c's and 8 d's, Yuk. Houston only has 1 c so I would be rollin to Houston. Good luck