you dont need a torch or press, just a big hammer. I did few kingpins in my time and every time I do it it gets easier. you do need another set of hands to help you. if you do take it anywhere to get done it will probably cost more than the van is worth. if you think you can do it yourself then go for it. they probably need to be greased otherwise they will fail. most common kingpin failure is not greasing it. does it have those grease nipples?
does it make noise when you hit bumps? Best way to check if they are bad is to lift the front and use a pry bar or something simmilar to yank the wheel up and down. stick in the wheel and try to lift it. someone should watch if the whole hub moves then yeah hey are bad. if the wheel only moves then its bearings. if youre alone lift the front and watch the wheels movement. when they get of the ground look at the bottom of the tire. if they move inwards then something is not right. | 
