If you can stand ramps, Harbor Freight has aluminum 6' ramps for about $100 (set, with coupon). I use them with my tilt trailer because it has a bed all the way across and the approach angle won't work.
U Haul will want to know what car is going on the trailer. I rented from them twice with the Birkin. I gave them the weight, dimensions of tire contact patches (inside and out, etc). They had to call HQ to get the OK, but finally did. They have 2 sizes of car haulers. Make sure the person you talk to is not thinking you want a tow-dolly. The only way to know if they will approve the mini van is to ask them.