Quoted from too-many-pins:

A 6x12 ramp door enclosed trailer is the "near perfect" trailer for most people and as long as you have room to park one and the ability to tow a trailer it is hands down the best way to move pinball machines. Rarely am I without at least one enclosed trailer and typically I have two or more around. If you are towing with a full size truck nothing beats a 7x16 "v" nose with tandem axles they tow better and ride nicer than a single axle trailer. But if you are towing with a mid size vehicle or don't really move all that much bigger stuff (or bigger loads) a 6x12 is the way to go.
Normally I pay the extra and get a heavy duty 6x12 with 2x4 box tubing frame. These days most companies are building 6x12 with a 2x3 frame and that just isn't really heavy duty enough to be truly safe. Up until around 2005 only "junk" brands used a 2x3 frame but now most trailer companies have changed over to the 2x3 frame unless you get a heavy duty trailer or order one and specify 2x4" frame.
7x16 trailers are the same way - they now use a 2x4" frame but should really be built on a 2x6" frame. Be careful when buying a trailer and be sure you are buying something that is built correctly. Cheap isn't always cheaper - saving a couple hundred when you are buying then bending a frame will not save you any money in the end!

Quoted from IdahoRealtor:

When it's only one or two pins, do you generally walk them in with legs on and transport them with the legs on, or always with the legs off?

Quoted from MT45:

As others have said - pickup is nice BUT ... getting the PB out of the bed can be a chore, risky to both the pinball and you, especially if doing it alone.
If you have a place to store it, a small trailer with a fold down gate makes it super easy. I have hauled in the bed and in the trailer and the trailer is 10x easier