... Up Hills:
Oh dear. You kind of need to use a very laborious 'pendulum' motion. Picture the 'Carriage' perpendicular to the track (or more accurately parallel to the hill gradient line, so that its neither pointing up or down). Okay, now accelerate getting it up to about 5km/h or hopefully more if you go down-hill very slightly initially. Now very smoothly turn to drive up the hill for about 1 metre if your lucky (usually less if it's a bugger of a hill
). Then when you come to a complete stop due to the, ah, hill - CAREFULLY let it roll backwards slowly whilst turning full lock, braking to ensure traction (and precious distance up the hill) isn't lost. Carefully get it to a spot again perpendicular (or VERY slightly pointing down hill) to the track and with the rear wheels just nearly touching the grass. You should be where you started, but a few centimetres higher up the hill ready for another 'swing'. Its kinda like a pendulum motion, being slightly powered in one direction of the motion, which means you can very slowly make your way higher up the hill! Sometimes it can feel like you're not getting higher though! Persistance is the game and eventually you'll get to the top which is sheer bliss. ...