I did something similar with a friend last night (Panorama City to San Francisco). We rented a tow dolly from U-Haul, and used his brother's Ford E-350 extended wheelbase van. Unfortunately the locations up here did not have any for rent. We had to rent a dolly in Santa Monica(!). The in-town rental fee is $40, with mileage the fee was $110. If you can rent the dolly at home, you can opt for the in-town rate and save a bunch of money.

The V10 motor averaged about 65mph (the dolly recommends a max speed of 45mph, but seemed very stable up to 75mph) up the five, which was a little fast for my tastes (I made the friend do all of the driving). The longer, heavier, and more powerful your tow vehicle is the happier you will be. The tow dolly had mechanically activated hydraulic brakes, but added 2,000 pounds to our load. If you're going to tow with a towbar or a dolly that'll only support two wheels... allow a much much longer distance for stopping.

FWIW I would never rent a van from U-Haul, ever. From what I could see their lack of maintenance is frightening, and from what I've heard it's worse than you would think. If you do rent a dolly, check the tire pressure before you leave. One of the tires on our dolly got very hot compared to the rest.

I imagine you wouldn't have a huge problem towing a brick with tow bar another brick (all four wheels of the towed vehicle on the ground). You would just have to limit your top speed and allow a lot more room for braking. As an added bonus, a car is bound to be more stable in the wind, and a LOT more comfortable. That Ford van was horrible.

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alex