"I am almost there!"
Translation:Jeg er der næsten!
This wouldn't work for an exclamation such as in this sentence.
Your sentence could be used if you were pointing to a location on a map: "Jeg er næsten der." (As opposed to being somewhere else on the map)
Seems ok to me. Sometimes adverbs can move around (c.f. "Flyet er her ikke." and "Flyet er ikke her." for "The plane isn't here.")
There's a difference between the two, though.
Flyet er her ikke = The plane isn't here (It is gone)
Flyet er ikke her = The plane isn't here (It must be somewhere else)
For example, if I went into a hangar and the plane was gone, I'd say: "Flyet er her ikke!" (The plane isn't here!) Then I'd go to the next hangar and ask a guy if my plane is in there. He would answer: "Nej, flyet er ikke her." (No, the plane isn't here)