Using a Canon point
M/M & A/I
Picking up from when Maria visits Madame Vivanne ( I hope that's the name) in EOTW ( forgot if that was the episode
Maria gets a different reading.
She was told that a major change was about to happen for her and her friends, and was told about the course of events to come ( as they happened on the show).
Believing the vision / and knowing that no one especially the aliens would believe her. Maria convinces Alex of this vision and they leave Roswell.
Due to failed dreamwalks from Isabel, the gang go about their lives hoping for leads as to find Alex & Maria.
Tess now having her plans screwed turns her attention to Kyle to complete her mission
While all this is happening Maria & Alex have been kidnapped and taken to Antar
Kivar has been the one to track them down and used a portal like in S3 to take them back. He plans to use them as bargain tools if Tess screws things up ( which she will
How you want to take things after an alternate departure is up to you.
Michael & Isabel form a stronger friendship over the loss of Alex & Maria in which both finally realise what each means to them.
Maria & Alex are to be saved and reunited with the group.
Candy & Gazer ending is a must
Kyle must not die from the warps.
Tess & Kivar must die. (especially Tess)
Baby never exists ( how is up to you
On a side note, there will be no complaints from me if you keep the Dreamer to a minimum when they're involved