The photo above shows the arrangement I settled on. The beauty of pallets is that you can make a variety of structures that allows you to practise a multitude of different moves: jumps, drops, gapping, pedal grabs etc. So what could you do on this setup?
What goes up...
Jumps and drops are very well catered for in the picture above. The pallets provide many different levels to jump up and drop off. First I worked on going up 1 pallet then on to 2. Anything above 3 was out of my range... until I learned to crank grab :)
Grab it while you can
The foreground arrangement was where learned to crank grab. The 2 pallets above the base layer were high enough for a Monty wheelset to land on without the tyre touching the ground, yet still low enough that jumping and landing the pedal and crank was relatively easy. Once I got that down I moved on to the higher 4 stack to the right to practise jumping and grabbing higher obstacles.
From here to there
The various stacks allowed gapping from one to the other and at different heights too.
Becoming a balanced individual
It's not too easy to see in the picture above but there is a 4" wide balance beam going from the main arrangement out to a 2 stack to the left. I tried to leave as much ground room on either side of the beam for those times when I came off before making it to the other side... thankfully! If you look at where the beam meets the 2 stack to the left you'll see it's placed on some bricks to support it. This alone wasn't at all safe as the beam could move and wobble. The easy solution was to buy a big set of door hinges and screw them in to either end of the beam and the pallets which kept the beam nice and stable. However, it did mean that the pallets couldn't be moved easily.
There are several other things I could have added:
A teeter-totter is kind of like a seesaw in that it's a beam placed over a balancing point. You ride up one side then the other end swings down to touch the ground as you reach the middle and ride down. This one I did actually make up. I took a round fence post and nailed 2 1' planks to it (taken from a spare pallet and cut to size) so it would sit on the level and not roll around. I then placed an 8' beam on the fence post to find it's balancing point. 2 blocks of wood were then nailed to the beam on either side of the fence post. This was to keep the beam on the fence post when ridden over and to stop it from twisting.
For these you need 2 sheets of wood (about 3"x2' is fine) fixed together at one end with sturdy hinges. These are then placed on the ground with the non hinged ends placed apart so you can jump on the narrow upper join. It's necessary to secure them in such a way that jumping on them doesn't collapse them. To do this you can attach 2 chains to either side of the boards so when they are spread out on the ground the chain is taught.
These consist of 2 circular wooden disks attached to a circular core and are used for storing cables - they get wound round the core and are protected by the circular disks on either end. They seem to come in 2 main sizes: small and huge. They are harder to get hold of than pallets but do make excellent gapping platforms. If you ask nicely then maybe you can get one from anywhere that works with large cables.