[bigjae1976]

There are a couple of things...

A 30 gallon tank will add almost 300lbs in fuel when full. Make sure you have enough gross weight capacity. Fuel in the tank will slosh and affect control of the trailer.

A fuel cell will likely not work very well as an external fuel tank. The fuel will expand and contract with temp changes. The biggest problem you will have is when the temp drops. Fuel tanks will generally collapse under vacuum so you need some sort of pressure relief/vacuum ventilation system. It needs to be sized correctly!!!

The biggest risk is static control. Static is created whenever fluid moves. So you will need to make sure the system is properly grounded.

Pumps rated for gasoline are expensive. Make sure its rated for gasoline! Most are rated for diesel and kersone.

DOT regulates gasoline transported for commerce. So if this is for a business (for the tax write off people) then DOT and OSHA might apply - there's a materials of trade exemption for small non-bulk quantities. I think you'd be ok with anything less than a 55gal drum. Not sure if you have to put the red 1202 symbol on the tank.