Very fast Toboggan from old Skis and out grown snowboard
First step was making cross members - I used Oak for strength but pine would work I think. cut wide enough to allow 1 inch gap between skis and board as shown then using sander or router clean up edges to feel more comfortable
Next would be to measure and mark hole pattern of snowboard inserts then get hardware long enough to grab all of the snowboard threads but not too long, avoid bottoming out - stainless button head M6 (Metric) work depending on your wood thickness you decide length
Next mount skis parallel to snowboard and drill right through then countersink holes - use stainless hardware again and then drill through ski tips and add thick rope for easy pulling up hills - the final option is to tie a used outdoor chair cushion to platform because hitting bumps really hurts
Good luck !
Acknowledgments, Credits, and Bibliography