I have started building the return track. I am still waiting on my 100+ feet of rail to come in the mail, so I have built this track by splicing together small lengths of track, which will later be replaced. The return track starts with a 4.5 foot climb up a hill, then down into a diving turn which sends it back in the right direction.
Because I am building outdoors, supports can be placed wherever I need them and then anchored in place by pounding k'nex rods into the ground. This eliminates the need for bulky bases and allows for strong tracks from very few pieces.