Here's what I'd do:1) Robin somehow finds out she's pregnant. When Ted goes to give her the locket, profess his love and be the hero, Robin tells him she's pregnant and is so excited. He realizes Robin and Barney belong together and gives the locket to Barney to give to Robin as a symbolic gesture of him truly letting Robin go.2) No idea with Marshall and Lily. Kind of a dumb situation IMO. Probably should have Marshall supporting her and going to Italy like she supported him through law school.3) Every character except Ted should meet his wife and be charmed by her. As each of their storylines wrap up, they should remark to each other that they found the perfect woman for Ted.4) Last 10-15 minutes of the show: Montage of Ted's past girlfriends with narrator Ted talking about why other people weren't "the one". Fade to Ted and "Mother" on the train and locking eyes. Narrator Ted says "But when you find the one, you'll know and it will all be worth it." Train Ted looks at the girl and says "Hi, I'm Ted." Narrator Ted comes back I'm while Train Ted and "Mother" fade while talking excitedly with each other. Narrator Ted: "And kids, THAT'S how I met your mother."That would pretty much satisfy me.