Ok, here's a few of my observations:
For both of your arrangements, there are some parts that could use harmonies. Measures 10 and 14 in your Map arrangement specifically. There are only a few parts (mostly the vocal parts) in "Walking the Plains." They're not really necessary, but it adds a little bit of extra depth to the arrangement.
I think that the synth vocal parts in "Walking the Plains" would probably sound better raised up an octave too.
In Measure 26 (and the other measure like that), the A should come on the 'and' of beat 2 instead of beat 3.
And last, starting from Measure 31, the right hand part of Piano 2 sounds a little off. I recognize the part you were trying to transcribe from the original and I think there's a few notes missing and a couple of incorrect rhythms.
Anyway, these are just suggestions so feel free to disagree with any of them.