Translation:I am on vacation on Kronos.
A great example of the unsuffixed verb as opposed to the imperfect: I wrongly put "I am vacationing on Kronos," which should be Qo'noSDaq jIghIQtaH.
Although now I see "I am on vacation on Kronos" is listed as the preferred answer. In my dialect of English, that is a direct synonym for my "I am vacationing." I must admit that I liked the very general translation I was given of "I vacation on Kronos."
'On vacation' and 'vacationing' mean the same thing. They're both present tense. They're both something you're doing at the moment.
If you 'vacation' on Kronos, that's more of a statement of something you've been known to do: "You went to Miami this year, Gladys? Wilbur and I have been known to vacation on Kronos from time to time."
"I am vacationing on Kronos," should be accepted. "I vacation on Kronos," should not.
Since there is no -taH suffix in this Klingon sentence, "I vacation on Kronos," may actually be the least controversial translation. Your argument actually argues against accepting "I am on vacation on Kronos," since that and, "I am vacationing on Kronos," both indicate a currently ongoing action and thus would be better represented with the -taH suffix.