Hello,
Actually to go to Kuelap, you will have to pass at Chachapoyas. Kuelap is a two and a half to three hour drive from Chachapoyas.
If you take the flight Lima - Jaen, which is a great idea, as you will be much quicker and more comfortable than taking a bus, you should find taxis at the airport in Jaen that bring you to Jaen city. From Jaen city you can take a combi that brings you to Chachapoyas. The cost should be 20 soles and the trip from Jaen to Chachapoyas takes three and a half hours. The cost of the flight depends on your time of booking and your flight dates. Have a look at the LATAM Airlines website and see which rates you can get for March.
Then you can stay overnight in Chachapoyas and take a day-tour the next day to Kuelap. I recommend to go with Turismo Explorer (they are directly on the Plaza) and the day-tour including transportation, guide, entrance and lunch is at 80 soles (rates 2016).
I hope this is helpful to prepare your trip for next year.
Happy travels,
Martina