How should I level the boat to sit on the trailer for towing ? The
low trailer tounge height behind my van keeps the trailer angled
downward in the front so should I offset this by adjusting the trailer
to raise the bow of the boat so the boat sits level relative to the
ground?

You should adjust the hitch so that the trailer sets level


The prop sits too low to the ground so the motor has to be tilted
while towing. Do you recommend using some kind of support from the
lower end to the trailer ?

They make a device called a transom saver (one manf.) for just this purpose


BC