Let's look now at the three cadenzas that come later in the movement. From a visual standpoint it's easy to see that each successive cadenza is more elaborate than the previous.
Therefore, it's smart to underplay the first one just a little. Not too long a hold on the F, not too slow to start with, not much accelerando or crescendo.
This leaves room for more of everything in the next two cadenzas. Longer hold on the F, slower start to the triplets, more crescendo and accelerando to the end. Note the ritardando molto at the end of the third cadenza. This can start earlier than indicated if you want -- on the last G and following.
Each cadenza is introduced by the three note sequence, D, E, F in quarter note triplets. I like to provide some direction to this introductory fanfare by playing the D and E as the latter part of a three-note quarter triplet group, giving the two notes a pickup feel as they approach the F. A slight crescendo towards the F in each case is helpful.
In the third cadenza, I use a simplified fingering for the E-D-E triplet alternation which occurs twice.
I return to a normal, full fingering for E in the next triplet group (D, E, F).