The moment I reach the fighting, or find my squadmates and want to help them fight, I need to leave my scooter or deconstruct it. Any place I can park it so it does not go waste? Once spawned, is the only way to get back the resources to deconstruct the vehicle?
There is no safe place to place vehicles if you want to leave them, so the best way is to just abandon them where they are not in the way of other vehicles, i.e. somewhere on the side of the road away from ammo towers and vehicle spawns.
For one-man transportation, the Flash is the best choice since the resource cost and spawn timer are so low that you don't have to worry about just deconstructing them and spawning a new one after capturing the base. They also have a very effective Radar upgrade which can make base assaults a lot easier if you just abandon them right next to the enemy base. If the enemy doesn't destroy it you always know where they are moving and if they do, well, 25 resources and an uncerted 5 minute timer - that can be certed down to a 0s timer - won't prevent you from spawning a new one once the base is in your control.
Just don't get into armor columns with a Flash since ramming any vehicle is almost certain death.