We rarely drive at freeway speeds, and stop every 5-20 miles. And that is with at least 500 lbs of gear in the cargo box of our van.
Tow vehicles are a bit of a Goldilocks issue - the one that is "just right" will differ from person to person, because everyone uses their trailer differently, and some people need the tow vehicle to fulfill other roles that may be more important than or as important as towing.
The important thing about it is that the power band for the torque is fairly flat - you get most of the torque available at low rpm, all the way through to high rpm. Whereas standard engines tend to deliver torque at the high end of the rpm range. The result of the latter is that your engine is working at high rpm when driving in the mountains or hilly regions. The former will run at lower rpm and when it is necessary to downshift it will result in a much smaller increase in engine speed (and less noticeable shift).
Above are a couple quotes that I believe are key to choosing the correct tow vehicle for you. Personally I drive a 2007 Toyota FJ Cruiser with automatic transmission (this is an automatic where all 5 gears can be manually selected if desired). This past summer I drove through 20 states and 5 provinces, for a total of 14,700 miles (Arizona, Nevada, Oregon, Idaho, Utah, Wyoming, Nebraska, Kansas, Iowa, Illinois, Wisconsin, Michigan, Ontario, Quebec, New Brunswick, Prince Edward Island, Nova Scotia, Maine, New Hampshire, Vermont, New York, Indiana, Missouri, Colorado, and New Mexico. Being retired, time wasn't an issue and I slept in the 560 for 73 consecutive nights (it was a trip of a lifetime, absolutely fantastic). I did take some day trips without the trailer, but the mileage while pulling my 560 was about 12,000 miles.
Most times I had to remind myself that the trailer was behind me. I prefer two lane roads to freeways, but when on freeways I limited my speed to 65 MPH. On flat terrain, cruise control was engaged a good deal of the time. When driving faster than 55 MPH, I generally placed the transmission in 4th gear, as 5th gear is basically an overdrive the help with fuel economy. This was done so as to not incur too much vehicle automatic shifting to maintain speed. The fuel economic was compromised by driving in 4th, but I believe it is easier on wear and tear on the drive train.
The FJ Cruiser has a greater height than the 560, so I don't think wind was as much a factor as the additional weight of the trailer was on fuel economy. I averaged about 2.5 MPG less with the trailer than without; however, remember that I drive slower on freeways than without the trailer, so the economy is probably slightly worse than calculated.
It was a solo trip and the FJ Cruiser contained a lot of items that would have been carried in the trailer with a lesser vehicle. The FJ Cruiser is somewhat of a panel truck and very convenience to storage extra items. Unfortunately, Toyota no longer manufacturers the FJ and has designated the Tacoma pickup and 4 Runner to fill the void.
The FJ is shorter than both, and this came in handy when I took the ferry from Digby, Nova Scotia to St. Johns, New Brunswick. My total length was under 30 feet, which is significant when calculating the crossing fare.
In conclusion, my recommendation for a tow vehicle is summarized in the quotes borrowed from
Inn42.
People ask what does "FJ" stand for, I say it is "Fantastic Journey."
