In the episode "The Getaway Almost" who was that person that Jackie puts in the back of the trunk. It looks like an older woman but I always thought she looked a little like Becky.

I believe you're referring to Jenna Elfman (Dharma & Greg).

Actually I'm talking about the opening scene of the episode where Roseanne, Jackie, Dan, and DJ are loading up the car. I always thought the girl Jackie puts in the trunk was Becky but then I thought wouldn't she be in the rest of the episode like on the parts with Mark.