Back in the eighties I lived in a mobile home much like the one you have on a small plot of land out in the country. I did what you did except that I skipped all the intermittent steps.
I dug a hole. Twelve foot wide...sixty five foot long...four foot deep...and parked my mobile home in it. No front or rear decks were needed. Just step out the door onto the ground.

I used a shovel and a wheelbarrow to do it.