Era 6 Preparation

Laboratory Level 25 is the max and you would be best to have it going into Era 6. Level 22 is an absolute minimum for Era 6. You will not get to OLYMPUS before the Endgame without at least Level 22. Laboratory Level 22 and one week of Plus Account will get you enough points to research the OLYMPUS and most upgrades.
Be sure to save enough money (9,000,000) to upgrade your Engine shed right after we hit Era 6.
Get Coupling. If you won't have Coupling by Era 6 but you can get it less than 2 days into Era 6, IMO you should finish the research for it. Many players who need more than 2 days to get Era 5 Coupling forget about it and research the LINDWORM.
Have at least 6-7 free tracks to begin Era 6. Or connect to all Era 6 RGs by using a Map Of Goods. Have at least 10-20 free tracks for the Endgame.