Heavy equipment will be your friend if you want to do this in a timely manner. I would suggest an excavator with thumb for popping the stumps up out of the ground and a dozer for leveling and general clean up. You could either pile and burn the stumps etc or dig a hole and bury them. If you bury realize that you will eventually have a lot of settling on that area and you do not want to erect any type structure over it.
Depending on your location the equipment can be rented. Our rental places in my area will rent down to the half day (four hours on the hour meter) or as long as you want the machine. Delivery of the equipment is generally not included in the rental cost but is an added expense.
I've never run equipment professionally in my life, but wouldn't hesitate to do it myself. I did grow up around it and have used several different machines over the years for various things. It takes
experience and practice to be "good", but for general land clearing if you take your time and learn the machine you
should have no problems.
ETA: I would compare costs of having someone do the job against the cost of renting the machines and doing it myself.