We've used & I recommend, taxidatum.com for transportation. Their rate is US$20 each way between LIM & Miaflores (you make arrangements with them ahead of time & pay the driver with cash). The traffic is lousy & the ride will be over an hour each way. It's subjective if it's worth it, but if it was me, I would leave Miaflores by 2 p.m. for 4:40 flight.