20k, you guys are hilarious. I agree - be VERY careful here. It is difficult for anybody to answer this w/o seeing it. Bring us some pics. To clear 1 solid acre of brush, BS and overgrowth of all kinds is about $5,000 out here. So I cannot imagine this is 20K. However, 20K divided by 5 years is 4K a year... so maybe. My prediction is that somebody is going to f-up and bid this thing way too low and get the job. If you really don't know be straight with the guy. Get him to give you $1000 and show him how much you can do for a grand and estimate the rest of the job from there. Also, get him to pay you in pieces so you don't spend a week of your life doing this and then get stiffed.