I did a 3000 km round trip from Northern Ontario to Saskatchewan and back last summer.
Truck is a 2016 Ram 1500 SLT CC, 4x4, 5.7, 8 speed, 3.21 rear.
Trailer is a 2016 Jayco Jayflight SLX 264BHW, loaded was about 5700lbs. Average of trip according to dashboard was 9.7 mpg. Cost $800 in gas...