This seems more like a gameplay change then a map change. In other words I don't think it is possible to change the travel speed in a specefic map. You might be able to do it through planetary bonusses or abilities, though that would require that the planets used in the map are some new ones. So it might be possible to do, but will be somewhat complicated.
Depending on the layout of the map you could also just move the planets closer to eachother, though you propably aalready thought of this.