This is a very easy to make and I didn't even need to buy anything. Inspiration for this was from freeza36 and Higgs Boston. Here's what you need:

Rolling Trash Can Wheels X1
Rolling Cart Wheels (They MUST be able to mount by screws) X1
2X4 (Big enough to lie down on) X1
Plywood (or any kind of flat wood, should be a little smaller than 2X4) X1
Screws X6
Nail (Kinda a carpet tack.) X1

(I put a pic of everything in the second picture.)

Thats basicly all you need besides a hill.

Step 1: Attach the Wheels

This is the hardest part. The rolling cart wheel is easy just use 4 out of the 6 screws to attach it. The trash can wheel is hard. There are many ways to attach it. The way I did it is taking a electric pipe securer and screw (you'll need extra screws) it to the 2X4 then hammer it flat. Get the nail and hammer it INTO the pipe securer and BAM! they're attached.

Step 2: Attach the Plywood

Or any flatwood in this case...

Use the rest of the 2 screws to screw into the flatwood and attach it to the 2X4.

Step 3: Enjoy!!!!

Enjoy your new hill board. Feel free to post mods as I am going to do so later. Pleas give credit though. Some of the mods coming up is:

Headlights
Taillights
Footrest
Padding

Please subscribe so you can know when I post them!