It was a couple weeks ago. (things have been hectic around here )

I have vague memories of the surroundings, but not the specifics of what was said.

First, my father died 25 years ago and except for a few instances shortly after his death I've had no contact, no dreams, nothing..until just recently.

I was at a gathering..strange kind of place, reminded me of a jungle setting.  I was interacting with others when my father came in.  I was so happy to see him and he seemed happy to see me also.

I told him he was home now and couldn't leave until after I did.

I woke up thinking how strange it was.  Had he been stuck somewhere all this time?  Was he now "home" and waiting for me to get "there" before he moved on to the next life?

He did die suddenly, unexpectedly in a car accident.  No lingering, instant death.  There were indications that he "knew" time was short though, through things he did in the weeks before hand, such as taking care of last minute things and visiting places he hadn't been to in years.

Also, I had not seen him for about 7 months before his death, though we had spoken on the phone many times.

Any thoughts?  Retrieval, dream or contact?

Of course it's too hard to evaluate someone else's experience, but my opinion is that this was contact.  I think this because you said you haven't dreamed of him in 25 years.  I think that when someone pops into a dream unexpectedly (meaning that you had no other reason to be dreaming of him) then it usually means it is contact. 

Have you had anymore insight into this dream?  What do you think you meant by telling him he is home now and couldn't leave until you do?

What is called dreams is another word for alternate realities. Alternate realities can be experienced in many ways on various concious levels. It sounds as if you were almost there fully lucid. Contact was made, a retrieval, my feeling is no, and maybe not needed. The alterstate was the way to make contact. In this case your dream state.
You can always do a incubation on this experience and return. All it is, is planning ahead, setting the intent before sleep, and go for it.
Doug