Partly agree with you that there might be a 'visibility' issue regarding CITC, but i think that could mainly be due to a lot of the activities being run in conjunction with other agencies (like the FA, Sport England etc).
I don't know anything about the 20 mile rule, so can't help you on that.
With regard to the Soccer Centre across the road from the school, whoever told you its for Failsworth School use
only is wrong. The school now has its own all weather pitches behind the school which they use. The school is still linked to the Soccer centre but its management and control falls more under the FA and Oldham council afaik. JFC's like Failsworth Dynamoes & Failsworth Villa use it extensively to train on (as well as the pitches behind the school), and you can still hire a pitch for a kickabout if required
http://www.failsworthlg.co.uk/2/Prices.html
Not sure if you know how JFC funding works, but the FA have been trying to encourage them for years to do this sort of thing. JFC's apply to the FA for 'Charter' accreditation and the higher the accreditation you have, the more funding you can get from them. A minimum number of teams etc is required for the basic level. You get higher levels by having womens or girls teams etc. The highest accreditation is reserved for those that run teams or facilities for people with disabilities. I don't know any local teams that have managed to do this or make a success of it.
Therefore, i think if the CITC were to be involved in something like this, it would be easier and more successful if it was run from the training complex.
Regarding transport, my girls were taken to the complex by the school on all occasions, but have heard that City/CITC have provided transport to there in some special circumstances for other groups.