Mini ramp
Hey i built a mini ramp about a year ago mine's 3ft high 20 somthing ft long and 8ft wide, i don't find 8ft long enough but you might also it needs to be atlest 4ft high otherwise its like riding banks i used these plans that show 4ft and 6ft designs aswell. www. rickdahlen .com
Its going to cost you around $1000 in wood (not treated by the way I wouldn't bother with massonite it's slipprey and gets wet like cardboard) there fair easy to build the plans are really descriptive. If your lands not level you need to build fair good foundations to keep it level also this can be expensive and time consuming. You will also need a tarp to keep it dry i put a lader in the middle of mine to make the water run tarps work well and save your money from buying treated wood, also to stop the wood rotting you should paint it.
I will put pictures of the foundations and ramp on my profile.
If you have any questions message me.