that kind of rough usage is a lot to ask of a forklift that only cost you $5000. in my opinion way too much. if you have a bobcat skidsteer you may want to look into an exhaust scrubber and forklift attachment, but it won't give you 15 feet.

i don't know what the construction safety regulations are in NY, but in Ontario forklifts must have their masts inspected at least every year and need to be maintained in safe operating condition to pass that inspection. whenever someone argues with me about whether they need a mast inspection or not, i always tell them that if they run their car on public roads without plates and insurance, they may not get caught the first, second or third day, but when they do get caught they will wish they had obeyed the law. I have never seen a $5000 used forklift that could meet your needs that was in safe operating condition. Good Luck...