BackPacker, I'm not sure your solution works. Reason being, that
AFAIK the CAA (UK) respond to the query of another CAA (the FAA in this case) directly and will not give you the required docs. Otherwise this whole procedure would be a farce. I got caught up in this situation last year, albeit in Africa. Sorted it out in the end, but the CAA quote 10 working days for dealing with a request. They will, however, expedite if their reply is required for training!
So the CAA validation process is 10 days minimum unless you are going for training. But that's the only more or less serious delay in the whole process that I can think of. Everything else, as far as I know, is smooth as clockwork. Fill in the form, attach copies, send to Oklahoma with the address of the FDSO you intend to use, show up at the FDSO for a final check and you get your FAA piggyback PPL issued right there and then:
http://www.faa.gov/licenses_certific..._verification/
http://www.caa.co.uk/default.aspx?ca...90&pageid=6273
Now for the standalone PPL. You are lucky, as the time to get an M-1 visa appointment at the US embassy in London, right now, seems to be three days instead of the six weeks that I experienced (in Amsterdam):
http://travel.state.gov/visa/temp/wa...ondon&x=68&y=9
To this, you need to add an average of five days for visa processing, according to this:
http://www.usembassy.org.uk/cons_new...niv/index.html
Then you need to show up at the flight school, get TSA fingerprinting done and an FAA medical (that means hanging around for another day) and then you are going to have to train at least five hours, possibly more because of the NQ and do the skills test before you are let loose for your flying holiday.
It's your call of course, but if this is just for a flying holiday and not for something serious like trying to obtain an FAA PPL/IR, I still think the piggyback method is the most convenient even though you seem to be lucky and processing times of both a piggyback and standalone PPL seem to be about equal right now.
And let's not talk about the cost difference.