You can use rollerskate wheels or skateboard wheels. Harder wheels are faster but also more slippery. The bigger the wheels, the faster they are. 66 mm is nice, but you can also use smaller ones. Sliders You will want to use some hard, durable plastic for sliding.
Skateboard rails are quite useable.
I have good experience with crow bars. I use some wood to put them in the right distance from the base. To bring all of the parts together, you need quite some bolts of different length. All bolts are countersunk screws. It' s important to countersink the washers.