i have a flat yard and a 6' high drop in. yours is probably different than mine but i just put some 2x4s horizontally up the back and made a ladder into it. stairs would probably be easier to use but the ladder is so easy to make.
don't put a dfd on a flat yard. it won't work the way you want it to.
^ you could make a little triangle wood piece to use as a kicker, cover it in turf and attach things on either side of the drop in that would hold it. they would be on the sides of the ramp so they wouldn't affect you going down it when you just want to hit a flat rail at the bottom or you could put the mini kicker in the holders and set the very high down flat down rail next to the drop in (the supports would have to be much sturdier than what i drew haha) but then you would be able to hit it like urban style and would still be able to remove it when you are done so you could hit other rails. it is a little far fetched and kind of dangerous but it the idea just popped into my head in school today when i thought about this and i was excited about it so i decided to post it. i'm not sure if your drop in would work for this, mine probably would, mine is 6 feet tall on flat ground like yours. i'll post a pic of mine.
Knife Show Volume 2 from Mike Benson on Vimeo.