Atatripp and Ontripp

If you ask which of the two is correct, onatrip is correct.

Onatrip is a fixed match, which means "on the road". For example, they are planing Gonatriptoguyananextmonth. They plan to travel to Guyana next month. No travel.

Goforatrip, "for" often means "for", focusing on traveling, which often means that the state of "going to travel" is not going, but going, while goonatrip focuses on the state, and the phrase "traveling" generally means that you have already traveled.