If you saw all the rivers with your NL holdem hand, odds are 1 RF in 30k hands
https://en.wikipedia.org/wiki/Poker_...rd_poker_hands
However, depending on the games you play and how you play 'em practical odds to make a royal flush could be maybe 1 in 100k hands. You could get a math person to estimate it more correctly if you really care
)
I personally like top set on non-full flush rather than having a Royal Flush because it's easier to extract value.