I went to Keukenof today. Great visit after 5 pm. I took some photos and have posted on Instagram for you to inspire you: feel free to ask questions. I also went Leiden from there nice town.
P.S. I bought an all day Netherlands travel card good on trains (IC trains cost 1 .40 euro supplement) trams and buses for 41 euros. That got me from Amsterdam to Rotterdam to Leiden to Keukenof and back to Amsterdam.
I am off to Switzerland on Easy Jet this morning.