Something like this might be suitable for getting the LT onto racks at the rear:
www.safetyline.com.au/tyre-step.html?gclid=EAIaIQobChMIrNHs0czC7AIVRq6WCh3HmgOvEAQYASABEgJf0vD_BwE.For the front, open the side door and use the van step.
Having seen kayaks and SUPs come off high vehicle roofs when the kayak/SUP was side-on to the wind, suggest you point into or away-from the wind, when loading/unloading. Also, never leave the LT unsecured to the racks whilst loading/unloading.
If the wind is strong, you might ask for assistance from others nearby. I've seen a SUP come off a rack and smack the car parked alongside, because the SUPer was too embarrassed to ask for help until it was too late.

Finally, you might use two tie-down straps at the front, as well as (at least) a single at the rear. At vehicle speeds, there's a lot of wind force underneath the front of the board, trying to push it up and off the rack.
Hope this helps.