20,000 was an estimate based off 20 hours of work at $500 per hour (time and bill that I estimated a cat would cost to run in wet, slushy snow).....and other expenses, so while it was an estimate it may be a little high.
Regardless I don't think its unreasonable to say a small jump would cost at least $10,000.....even if a jump were to be built in 5 hours, and it were to have an hour of maintenance a day by a cat for two weeks there's your 20 hours.