$50-100 per hive? Did you include cost of equipment? You're worth that little?
Try it this way...$50 per hour times how many hours per hive? Plus cost of equipment. You have to estimate hours spent on the hive. I'd use $50 as a minimum since you will spend probably twice as many hours as you plan on. And the drive time generally isn't included in the hours, but you can write off the mileage. Plus you have to pay income taxes on that hourly rate, PLUS don't forget the 15% independent contractor tax (to cover social security, etc).
If the cost is really high, you might want to scale back the number of hives.
Michael's suggestion of a lump sum bid is a good one and lets everyone know what to expect.
Formula is: (Hours x Cost per Hour) + Direct Expense = Lump Sum bid
If $50 seems high, you should know that lawyers charge $400-450 and engineers charge $200-$300 per hour. Engineering consultants are now charging about $60-70 for secretarial and $90-100 for technicians, which are their lowest brackets.
You are an experienced beekeeper, one of very few in the country, compared to all the lawyers and engineers. This is a dangerous job (dangerous I tell you!) and of high social value. Don't undersell yourself. You're worth at least $100 an hour, though they might not pay that. How successful is this little resort? Do they want an observation hive, too?