[swordtart]

You can probably adapt other rules systems that specialise in GM-less or solo play (which is in effect GM-less with an extra player) to CW as well.

These are as diverse as Solo wargaming articles (Donald Featherstone had a whole book on it IIRC), to solo RP games (e.g. Space Trader for Traveller) to cooperative board games. There is free software available to create your own choose-your-own-adventure books.

As the GM for CW I generally have to play multiple enemy vehicles (and often multiple factions), so I have plenty of practice in the even-handedness required for this type of gaming.

If you are looking for random encounters you might also consider Vehicle Guide volume 1. This book was supposed to represent the standard designs you might be expected to encounter on a daily basis. It is sometimes referenced in the ADQ scenarios. The designs can be outdated, frequently sub-optimal and sometimes illegal (it depends on which version of the rules you are running them against), but this isn't unreasonable if you are representing random traffic of variable. The later Vehicle Guides are less useful as the designs are either overly specialised or are badly illegal (especially in VG3).