I wrote a short article over on Medium here, but here is a quick summary. Of course the whole series is like an abstract painting with various triggers that each viewer will pick up on and read in their own way.

Having said that, there are a few things in the epilogue that suggest what we see is quite straightforward and is simply taking place a few years in the future:

- "Is it future or is it past?" It is the future.

- When Dale and Carrie arrive at Twin Peaks, we see a shot of a modern gas station which is shortly followed by the Double R Diner which is closed (we don't know the exact time, but it seems to early to be closed given that the Chalfonts are still awake). Is this hinting that what we see is a few years down the line, Ed and Norma made true on their promise to retire, Big Ed's Gas Farm is now a modern corporate gas station and the Double R is simply closed (maybe it will be bought by "Norma's" franchise).

- Sarah has moved out of the Palmer house. It passed onto the Chalfonts and now the Tremonds. The Tremonds have always been interested in the Palmer family. We don't see the voice behind the door, could it be the Grandson Tremond now he is older? Or his son? Maybe Alice is his wife? We don't know, they don't give us enough information! But what we do know for sure is Sarah doesn't live there now, and the house has belonged to the Chalfonts, then the Tremonds. The most simple explanation being the passing of time and new owners. Dale seems to work this out as a possibility at the end of the scene when he asks "What year is this?"

- The original plans for Season 3 back in the 1990s suggested that Sheryl Lee would return to play a third cousin with red hair. The red hair trait was obviously passed onto the Diane character, but what if Carrie still represents this third, estranged cousin idea?

- Carrie doesn't remember the Palmer name, but she does react when she hears the name Sarah. Later in the car she starts to reminisce on her youth. Finally after a few minutes she suddenly has a bad reaction to the Palmer house and begins screaming (we don't know for sure if the voice whispering Laura in the wind is her imagination, her memory, her identity breaking down, from the Tremonds, from another spirit or anything that might represent, it's completely up to the viewer to interpret). A very simple explanation is that over the course of the day Cooper triggered a repressed childhood memory of the bad times Carrie spent at the Palmer house with her cousins, and she is beginning to remember now. Her screaming is a traumatic reaction to the memory resurfacing.

- Carrie has a white horse statue on her shelf, suggesting a connection to the Palmer women. (And maybe also the woodsman's poem?)

- In the credits Carrie Page is clearly listed as a specific character separate from Laura. It is not even "Laura Palmer/Carrie Page - Sheryl Lee" on one line; each of the two characters gets their own line. Why did they separate like this? Are we supposed to view them as two separate individuals?

- If Carrie is the third cousin this gives much more weight to the "She is my cousin" and "Watch out for my cousin" lines from the original series!

- Laura was named after Otto Preminger's film, Maddy after Vertigo. Apart from the obvious, is Carrie also a film character reference?

- Laura disappears in the woods. The Fireman's clues lead Dale to Carrie's house. 430 miles seems to be a portal to a motel. This motel seems to be a gateway that leads to different realities or time periods. Diane helps Dale through to the correct time period in a ritual that seems to be mentioned in The Secret History book. The series has shown how traveling between planes can scramble your brain, so perhaps Dale's sluggishness is simply this. The Richard & Linda note reminds him of the Fireman's clue, and his mission. I am not sure if Dale and Diane are Richard and Linda - if you want a Lynchian Lost Mulholland EMPIRE identity-crash type ending then it fits. It may just be a clue like the Giant's "smiling bag" in which something Dale will recognise is used to point him in the right direction. Shortly after the word "Judy" points him to the diner. Interesting to note that Carrie is not there, but hiding out at home - in front of the house is the #6 electric pole we saw in Andy's vision. It suggests that the Fireman is pointing Dale to finding Carrie. I wrote more about this on Medium.

- The season has dealt with doubles, but there are also many triples in the show - three Dales, three pink Mitchum girls, three co-ordinates, three clues, three bug symbols, the #6 pole appears in three locations and in Andy's vision we see an edit of the same pole three times.  There are probably many more examples of three. It is season three! Does this mean Carrie is a third cousin?

SUMMARY

Like any good abstract painting, I think there are a number of triggers that can lead to various interpretations.

One is a Mulholland Drive-type ending where Carrie is Laura and the whole thing is a dream to hide trauma, this is in line with Lynch's recent work over the last 20 years.

Another idea is that it is somehow connected to the alternate realities mentioned on Bill Hasting's website.

A third idea is the one above, just that it is simply a few years in the future and Carrie is Carrie, not Laura.

A fourth idea is that the whole thing is a meta commentary on TV, the state of the world and the phenomena of Twin Peaks itself.

Probably there is a bit of all four of these in it.

Why I think it might be the future: basically because Dale starts to work things out and asks "What year is this?" like he just realises they are in the right place but wrong time.

The original run had it's "See you in 25 years" line, which always kept it open for a possible Season 3. Perhaps "What year is this?" is a possible opening for Season 4. If a Season 4 is never made then a Mulholland Drive type ending can bring closure to the series as it is. If a Season 4 is commissioned, then perhaps we will see Dale and Carrie try to find Laura, rescue Audrey, track down Sarah, and deal with Judy, the mother creature, the frog-bug and whatever else. 

Series 3 was partly about de-typecasting Kyle McLachlan by giving him various characters to play. Perhaps a Series 4 will do a similar thing with Sheryl Lee.