SPOILERS How Could Doug Have Planned His Journey Better?
I've pointed out elsewhere that current timeline Doug 1.0 (before he becomes future Doug 2.0) should have planned his trip better. Although... A better planned trip might cause there to be two viable Doug's surviving and existing in one timeline.
As time is running out, there seems to be "no real plan." His earlier experiences at Oerstadt's bait shop may dictate to Doug that he needs to steal the ambulance.
Better plans?
Doug steals the ambulance and gun but no cell phone. Stealing a cell phone is like stealing basic equipment. With a cell phone, he could have called ANYBODY to help him. To get around the size/weight limitations and any possible memory issues, he could have written phone numbers on his body just as "REVIVE ME" was written. In all his years in law enforcement, he has to have one or two trusted people who "owe him one" OR whom would do anything "no questions asked."
In almost ALL time travel stories, movies, episodes, etc., where the same character of more than one timeline exist in one timeline (like the two Dougs), one of the characters (1.0 or 2.0) has to die. The "suspense" is in: Who survives and how? Either Doug could have died, heroically. The question is how to write in such a fashion which hasn't been seen 20 times already.