We DCF's in 2004, so it's been a few years.
However, Cookie is correct; once the paperwork was filed, DH was not able to visit the US. We stayed in the UK as a family until our house sold and the immigration process was complete. I did, however, make a trip to the US by myself to buy a house as DH was not allowed to travel.
Also, and I realize that this may have changed, but it was required that the US spouse had to reside in the UK for two years to be eligible to file through the London Embassy. This may have changed, but if it hasn't, you should know this.
I know that you have your tickets purchased already. However, you may need some time to research everything so that you don't make a decision in haste that you may regret in the future.
Good luck, whatever you decide to do.