One option for Backtrack is to simply invert the colours:
The combat condition tokens already have a red background, but they are a different shape, a different shade of red, and are never placed on map tiles, like Backtrack.
This way, all tokens that are used on map tiles are orange with either red or white graphics, except for Backtrack, which, uniquely among map tokens, is red. But it still stays within the red/orange scheme of other map tokens.
Of course, it could just have a unique colour altogether. Keeping the original pink in mind, these purple/pink versions might work:
I like a consistent colour scheme, but I also understand the need to be idiot proof!
Here’s what these options would look like on top of the different biomes:
